Source/WebCore/page/FrameView.cpp

   1 /*
   2  * Copyright (C) 1998, 1999 Torben Weis <weis@kde.org>
   3  *                     1999 Lars Knoll <knoll@kde.org>
   4  *                     1999 Antti Koivisto <koivisto@kde.org>
   5  *                     2000 Dirk Mueller <mueller@kde.org>
   6  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2013 Apple Inc. All rights reserved.
   7  *           (C) 2006 Graham Dennis (graham.dennis@gmail.com)
   8  *           (C) 2006 Alexey Proskuryakov (ap@nypop.com)
   9  * Copyright (C) 2009 Google Inc. All rights reserved.
  10  *
  11  * This library is free software; you can redistribute it and/or
  12  * modify it under the terms of the GNU Library General Public
  13  * License as published by the Free Software Foundation; either
  14  * version 2 of the License, or (at your option) any later version.
  15  *
  16  * This library is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  19  * Library General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU Library General Public License
  22  * along with this library; see the file COPYING.LIB.  If not, write to
  23  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  24  * Boston, MA 02110-1301, USA.
  25  */
  26
  27 #include "config.h"
  28 #include "FrameView.h"
  29
  30 #include "AXObjectCache.h"
  31 #include "AnimationController.h"
  32 #include "BackForwardController.h"
  33 #include "CachedImage.h"
  34 #include "CachedResourceLoader.h"
  35 #include "Chrome.h"
  36 #include "ChromeClient.h"
  37 #include "DOMWindow.h"
  38 #include "DocumentMarkerController.h"
  39 #include "EventHandler.h"
  40 #include "FloatRect.h"
  41 #include "FocusController.h"
  42 #include "FontCache.h"
  43 #include "FontLoader.h"
  44 #include "FrameLoader.h"
  45 #include "FrameLoaderClient.h"
  46 #include "FrameSelection.h"
  47 #include "FrameTree.h"
  48 #include "GraphicsContext.h"
  49 #include "HTMLDocument.h"
  50 #include "HTMLFrameElement.h"
  51 #include "HTMLFrameSetElement.h"
  52 #include "HTMLNames.h"
  53 #include "HTMLPlugInImageElement.h"
  54 #include "InspectorClient.h"
  55 #include "InspectorController.h"
  56 #include "InspectorInstrumentation.h"
  57 #include "Logging.h"
  58 #include "MainFrame.h"
  59 #include "MemoryCache.h"
  60 #include "MemoryPressureHandler.h"
  61 #include "OverflowEvent.h"
  62 #include "ProgressTracker.h"
  63 #include "RenderEmbeddedObject.h"
  64 #include "RenderFullScreen.h"
  65 #include "RenderIFrame.h"
  66 #include "RenderLayer.h"
  67 #include "RenderLayerBacking.h"
  68 #include "RenderLayerCompositor.h"
  69 #include "RenderSVGRoot.h"
  70 #include "RenderScrollbar.h"
  71 #include "RenderScrollbarPart.h"
  72 #include "RenderStyle.h"
  73 #include "RenderText.h"
  74 #include "RenderTheme.h"
  75 #include "RenderView.h"
  76 #include "RenderWidget.h"
  77 #include "SVGDocument.h"
  78 #include "SVGSVGElement.h"
  79 #include "ScrollAnimator.h"
  80 #include "ScrollingCoordinator.h"
  81 #include "Settings.h"
  82 #include "StyleResolver.h"
  83 #include "TextResourceDecoder.h"
  84 #include "TextStream.h"
  85 #include "TiledBacking.h"
  86
  87 #include <wtf/CurrentTime.h>
  88 #include <wtf/Ref.h>
  89 #include <wtf/TemporaryChange.h>
  90
  91 #if USE(TILED_BACKING_STORE)
  92 #include "TiledBackingStore.h"
  93 #endif
  94
  95 #if ENABLE(TEXT_AUTOSIZING)
  96 #include "TextAutosizer.h"
  97 #endif
  98
  99 #if PLATFORM(IOS)
 100 #include "DocumentLoader.h"
 101 #include "LegacyTileCache.h"
 102 #include "MemoryCache.h"
 103 #include "MemoryPressureHandler.h"
 104 #include "SystemMemory.h"
 105 #endif
 106
 107 namespace WebCore {
 108
 109 using namespace HTMLNames;
 110
 111 double FrameView::sCurrentPaintTimeStamp = 0.0;
 112
 113 // The maximum number of updateEmbeddedObjects iterations that should be done before returning.
 114 static const unsigned maxUpdateEmbeddedObjectsIterations = 2;
 115
 116 static RenderLayer::UpdateLayerPositionsFlags updateLayerPositionFlags(RenderLayer* layer, bool isRelayoutingSubtree, bool didFullRepaint)
 117 {
 118     RenderLayer::UpdateLayerPositionsFlags flags = RenderLayer::defaultFlags;
 119     if (didFullRepaint) {
 120         flags &= ~RenderLayer::CheckForRepaint;
 121         flags |= RenderLayer::NeedsFullRepaintInBacking;
 122     }
 123     if (isRelayoutingSubtree && layer->enclosingPaginationLayer(RenderLayer::IncludeCompositedPaginatedLayers))
 124         flags |= RenderLayer::UpdatePagination;
 125     return flags;
 126 }
 127
 128 Pagination::Mode paginationModeForRenderStyle(const RenderStyle& style)
 129 {
 130     EOverflow overflow = style.overflowY();
 131     if (overflow != OPAGEDX && overflow != OPAGEDY)
 132         return Pagination::Unpaginated;
 133
 134     bool isHorizontalWritingMode = style.isHorizontalWritingMode();
 135     TextDirection textDirection = style.direction();
 136     WritingMode writingMode = style.writingMode();
 137
 138     // paged-x always corresponds to LeftToRightPaginated or RightToLeftPaginated. If the WritingMode
 139     // is horizontal, then we use TextDirection to choose between those options. If the WritingMode
 140     // is vertical, then the direction of the verticality dictates the choice.
 141     if (overflow == OPAGEDX) {
 142         if ((isHorizontalWritingMode && textDirection == LTR) || writingMode == LeftToRightWritingMode)
 143             return Pagination::LeftToRightPaginated;
 144         return Pagination::RightToLeftPaginated;
 145     }
 146
 147     // paged-y always corresponds to TopToBottomPaginated or BottomToTopPaginated. If the WritingMode
 148     // is horizontal, then the direction of the horizontality dictates the choice. If the WritingMode
 149     // is vertical, then we use TextDirection to choose between those options.
 150     if (writingMode == TopToBottomWritingMode || (!isHorizontalWritingMode && textDirection == RTL))
 151         return Pagination::TopToBottomPaginated;
 152     return Pagination::BottomToTopPaginated;
 153 }
 154
 155 FrameView::FrameView(Frame& frame)
 156     : m_frame(&frame)
 157     , m_canHaveScrollbars(true)
 158     , m_layoutTimer(this, &FrameView::layoutTimerFired)
 159     , m_layoutRoot(0)
 160     , m_layoutPhase(OutsideLayout)
 161     , m_inSynchronousPostLayout(false)
 162     , m_postLayoutTasksTimer(this, &FrameView::postLayoutTimerFired)
 163     , m_updateEmbeddedObjectsTimer(this, &FrameView::updateEmbeddedObjectsTimerFired)
 164     , m_isTransparent(false)
 165     , m_baseBackgroundColor(Color::white)
 166     , m_mediaType("screen")
 167     , m_overflowStatusDirty(true)
 168     , m_viewportRenderer(0)
 169     , m_wasScrolledByUser(false)
 170     , m_inProgrammaticScroll(false)
 171     , m_safeToPropagateScrollToParent(true)
 172     , m_isTrackingRepaints(false)
 173     , m_shouldUpdateWhileOffscreen(true)
 174     , m_exposedRect(FloatRect::infiniteRect())
 175     , m_deferSetNeedsLayouts(0)
 176     , m_setNeedsLayoutWasDeferred(false)
 177     , m_speculativeTilingEnabled(false)
 178     , m_speculativeTilingEnableTimer(this, &FrameView::speculativeTilingEnableTimerFired)
 179 #if PLATFORM(IOS)
 180     , m_useCustomFixedPositionLayoutRect(false)
 181     , m_useCustomSizeForResizeEvent(false)
 182 #endif
 183     , m_hasOverrideViewportSize(false)
 184     , m_shouldAutoSize(false)
 185     , m_inAutoSize(false)
 186     , m_didRunAutosize(false)
 187     , m_autoSizeFixedMinimumHeight(0)
 188     , m_headerHeight(0)
 189     , m_footerHeight(0)
 190     , m_milestonesPendingPaint(0)
 191     , m_visualUpdatesAllowedByClient(true)
 192     , m_scrollPinningBehavior(DoNotPin)
 193 {
 194     init();
 195
 196     if (frame.isMainFrame()) {
 197         ScrollableArea::setVerticalScrollElasticity(m_frame->page() ? m_frame->page()->verticalScrollElasticity() : ScrollElasticityAllowed);
 198         ScrollableArea::setHorizontalScrollElasticity(m_frame->page() ? m_frame->page()->horizontalScrollElasticity() : ScrollElasticityAllowed);
 199     }
 200 }
 201
 202 PassRefPtr<FrameView> FrameView::create(Frame& frame)
 203 {
 204     RefPtr<FrameView> view = adoptRef(new FrameView(frame));
 205     view->show();
 206     return view.release();
 207 }
 208
 209 PassRefPtr<FrameView> FrameView::create(Frame& frame, const IntSize& initialSize)
 210 {
 211     RefPtr<FrameView> view = adoptRef(new FrameView(frame));
 212     view->Widget::setFrameRect(IntRect(view->location(), initialSize));
 213     view->show();
 214     return view.release();
 215 }
 216
 217 FrameView::~FrameView()
 218 {
 219     if (m_postLayoutTasksTimer.isActive())
 220         m_postLayoutTasksTimer.stop();
 221
 222     removeFromAXObjectCache();
 223     resetScrollbars();
 224
 225     // Custom scrollbars should already be destroyed at this point
 226     ASSERT(!horizontalScrollbar() || !horizontalScrollbar()->isCustomScrollbar());
 227     ASSERT(!verticalScrollbar() || !verticalScrollbar()->isCustomScrollbar());
 228
 229     setHasHorizontalScrollbar(false); // Remove native scrollbars now before we lose the connection to the HostWindow.
 230     setHasVerticalScrollbar(false);
 231
 232     ASSERT(!m_scrollCorner);
 233
 234     ASSERT(frame().view() != this || !frame().contentRenderer());
 235 }
 236
 237 void FrameView::reset()
 238 {
 239     m_cannotBlitToWindow = false;
 240     m_isOverlapped = false;
 241     m_contentIsOpaque = false;
 242     m_layoutTimer.stop();
 243     m_layoutRoot = 0;
 244     m_delayedLayout = false;
 245     m_needsFullRepaint = true;
 246     m_layoutSchedulingEnabled = true;
 247     m_layoutPhase = OutsideLayout;
 248     m_inSynchronousPostLayout = false;
 249     m_layoutCount = 0;
 250     m_nestedLayoutCount = 0;
 251     m_postLayoutTasksTimer.stop();
 252     m_updateEmbeddedObjectsTimer.stop();
 253     m_firstLayout = true;
 254     m_firstLayoutCallbackPending = false;
 255     m_wasScrolledByUser = false;
 256     m_safeToPropagateScrollToParent = true;
 257     m_lastViewportSize = IntSize();
 258     m_lastZoomFactor = 1.0f;
 259     m_isTrackingRepaints = false;
 260     m_trackedRepaintRects.clear();
 261     m_lastPaintTime = 0;
 262     m_paintBehavior = PaintBehaviorNormal;
 263     m_isPainting = false;
 264     m_visuallyNonEmptyCharacterCount = 0;
 265     m_visuallyNonEmptyPixelCount = 0;
 266     m_isVisuallyNonEmpty = false;
 267     m_firstVisuallyNonEmptyLayoutCallbackPending = true;
 268     m_maintainScrollPositionAnchor = 0;
 269 }
 270
 271 void FrameView::removeFromAXObjectCache()
 272 {
 273     if (AXObjectCache* cache = axObjectCache())
 274         cache->remove(this);
 275 }
 276
 277 void FrameView::resetScrollbars()
 278 {
 279     // Reset the document's scrollbars back to our defaults before we yield the floor.
 280     m_firstLayout = true;
 281     setScrollbarsSuppressed(true);
 282     if (m_canHaveScrollbars)
 283         setScrollbarModes(ScrollbarAuto, ScrollbarAuto);
 284     else
 285         setScrollbarModes(ScrollbarAlwaysOff, ScrollbarAlwaysOff);
 286     setScrollbarsSuppressed(false);
 287 }
 288
 289 void FrameView::resetScrollbarsAndClearContentsSize()
 290 {
 291     resetScrollbars();
 292
 293     setScrollbarsSuppressed(true);
 294     setContentsSize(IntSize());
 295     setScrollbarsSuppressed(false);
 296 }
 297
 298 void FrameView::init()
 299 {
 300     reset();
 301
 302     m_margins = LayoutSize(-1, -1); // undefined
 303     m_size = LayoutSize();
 304
 305     // Propagate the marginwidth/height and scrolling modes to the view.
 306     Element* ownerElement = frame().ownerElement();
 307     if (ownerElement && (ownerElement->hasTagName(frameTag) || ownerElement->hasTagName(iframeTag))) {
 308         HTMLFrameElementBase* frameElt = toHTMLFrameElementBase(ownerElement);
 309         if (frameElt->scrollingMode() == ScrollbarAlwaysOff)
 310             setCanHaveScrollbars(false);
 311         LayoutUnit marginWidth = frameElt->marginWidth();
 312         LayoutUnit marginHeight = frameElt->marginHeight();
 313         if (marginWidth != -1)
 314             setMarginWidth(marginWidth);
 315         if (marginHeight != -1)
 316             setMarginHeight(marginHeight);
 317     }
 318
 319     Page* page = frame().page();
 320     if (page && page->chrome().client().shouldPaintEntireContents())
 321         setPaintsEntireContents(true);
 322 }
 323
 324 void FrameView::prepareForDetach()
 325 {
 326     detachCustomScrollbars();
 327     // When the view is no longer associated with a frame, it needs to be removed from the ax object cache
 328     // right now, otherwise it won't be able to reach the topDocument()'s axObject cache later.
 329     removeFromAXObjectCache();
 330
 331     if (frame().page()) {
 332         if (ScrollingCoordinator* scrollingCoordinator = frame().page()->scrollingCoordinator())
 333             scrollingCoordinator->willDestroyScrollableArea(this);
 334     }
 335 }
 336
 337 void FrameView::detachCustomScrollbars()
 338 {
 339     Scrollbar* horizontalBar = horizontalScrollbar();
 340     if (horizontalBar && horizontalBar->isCustomScrollbar())
 341         setHasHorizontalScrollbar(false);
 342
 343     Scrollbar* verticalBar = verticalScrollbar();
 344     if (verticalBar && verticalBar->isCustomScrollbar())
 345         setHasVerticalScrollbar(false);
 346
 347     m_scrollCorner = nullptr;
 348 }
 349
 350 void FrameView::recalculateScrollbarOverlayStyle()
 351 {
 352     ScrollbarOverlayStyle oldOverlayStyle = scrollbarOverlayStyle();
 353     ScrollbarOverlayStyle overlayStyle = ScrollbarOverlayStyleDefault;
 354
 355     Color backgroundColor = documentBackgroundColor();
 356     if (backgroundColor.isValid()) {
 357         // Reduce the background color from RGB to a lightness value
 358         // and determine which scrollbar style to use based on a lightness
 359         // heuristic.
 360         double hue, saturation, lightness;
 361         backgroundColor.getHSL(hue, saturation, lightness);
 362         if (lightness <= .5 && backgroundColor.alpha() > 0)
 363             overlayStyle = ScrollbarOverlayStyleLight;
 364     }
 365
 366     if (oldOverlayStyle != overlayStyle)
 367         setScrollbarOverlayStyle(overlayStyle);
 368 }
 369
 370 void FrameView::clear()
 371 {
 372     setCanBlitOnScroll(true);
 373
 374     reset();
 375
 376     setScrollbarsSuppressed(true);
 377
 378 #if PLATFORM(IOS)
 379     // To avoid flashes of white, disable tile updates immediately when view is cleared at the beginning of a page load.
 380     // Tiling will be re-enabled from UIKit via [WAKWindow setTilingMode:] when we have content to draw.
 381     if (LegacyTileCache* tileCache = legacyTileCache())
 382         tileCache->setTilingMode(LegacyTileCache::Disabled);
 383 #endif
 384 }
 385
 386 bool FrameView::didFirstLayout() const
 387 {
 388     return !m_firstLayout;
 389 }
 390
 391 void FrameView::invalidateRect(const IntRect& rect)
 392 {
 393     if (!parent()) {
 394         if (HostWindow* window = hostWindow())
 395             window->invalidateContentsAndRootView(rect);
 396         return;
 397     }
 398
 399     RenderWidget* renderer = frame().ownerRenderer();
 400     if (!renderer)
 401         return;
 402
 403     IntRect repaintRect = rect;
 404     repaintRect.move(renderer->borderLeft() + renderer->paddingLeft(),
 405                      renderer->borderTop() + renderer->paddingTop());
 406     renderer->repaintRectangle(repaintRect);
 407 }
 408
 409 void FrameView::setFrameRect(const IntRect& newRect)
 410 {
 411     IntRect oldRect = frameRect();
 412     if (newRect == oldRect)
 413         return;
 414
 415 #if ENABLE(TEXT_AUTOSIZING)
 416     // Autosized font sizes depend on the width of the viewing area.
 417     if (newRect.width() != oldRect.width()) {
 418         Page* page = frame().page();
 419         if (frame().isMainFrame() && page->settings().textAutosizingEnabled()) {
 420             for (Frame* frame = &page->mainFrame(); frame; frame = frame->tree().traverseNext())
 421                 frame().document()->textAutosizer()->recalculateMultipliers();
 422         }
 423     }
 424 #endif
 425
 426     ScrollView::setFrameRect(newRect);
 427
 428     updateScrollableAreaSet();
 429
 430     if (RenderView* renderView = this->renderView()) {
 431         if (renderView->usesCompositing())
 432             renderView->compositor().frameViewDidChangeSize();
 433     }
 434 }
 435
 436 #if ENABLE(REQUEST_ANIMATION_FRAME)
 437 bool FrameView::scheduleAnimation()
 438 {
 439     if (HostWindow* window = hostWindow()) {
 440         window->scheduleAnimation();
 441         return true;
 442     }
 443     return false;
 444 }
 445 #endif
 446
 447 void FrameView::setMarginWidth(LayoutUnit w)
 448 {
 449     // make it update the rendering area when set
 450     m_margins.setWidth(w);
 451 }
 452
 453 void FrameView::setMarginHeight(LayoutUnit h)
 454 {
 455     // make it update the rendering area when set
 456     m_margins.setHeight(h);
 457 }
 458
 459 bool FrameView::frameFlatteningEnabled() const
 460 {
 461     return frame().settings().frameFlatteningEnabled();
 462 }
 463
 464 bool FrameView::isFrameFlatteningValidForThisFrame() const
 465 {
 466     if (!frameFlatteningEnabled())
 467         return false;
 468
 469     HTMLFrameOwnerElement* owner = frame().ownerElement();
 470     if (!owner)
 471         return false;
 472
 473     // Frame flattening is valid only for <frame> and <iframe>.
 474     return owner->hasTagName(frameTag) || owner->hasTagName(iframeTag);
 475 }
 476
 477 bool FrameView::avoidScrollbarCreation() const
 478 {
 479     // with frame flattening no subframe can have scrollbars
 480     // but we also cannot turn scrollbars off as we determine
 481     // our flattening policy using that.
 482     return isFrameFlatteningValidForThisFrame();
 483 }
 484
 485 void FrameView::setCanHaveScrollbars(bool canHaveScrollbars)
 486 {
 487     m_canHaveScrollbars = canHaveScrollbars;
 488     ScrollView::setCanHaveScrollbars(canHaveScrollbars);
 489 }
 490
 491 void FrameView::updateCanHaveScrollbars()
 492 {
 493     ScrollbarMode hMode;
 494     ScrollbarMode vMode;
 495     scrollbarModes(hMode, vMode);
 496     if (hMode == ScrollbarAlwaysOff && vMode == ScrollbarAlwaysOff)
 497         setCanHaveScrollbars(false);
 498     else
 499         setCanHaveScrollbars(true);
 500 }
 501
 502 PassRefPtr<Scrollbar> FrameView::createScrollbar(ScrollbarOrientation orientation)
 503 {
 504     if (!frame().settings().allowCustomScrollbarInMainFrame() && frame().isMainFrame())
 505         return ScrollView::createScrollbar(orientation);
 506
 507     // FIXME: We need to update the scrollbar dynamically as documents change (or as doc elements and bodies get discovered that have custom styles).
 508     Document* doc = frame().document();
 509
 510     // Try the <body> element first as a scrollbar source.
 511     Element* body = doc ? doc->body() : 0;
 512     if (body && body->renderer() && body->renderer()->style().hasPseudoStyle(SCROLLBAR))
 513         return RenderScrollbar::createCustomScrollbar(this, orientation, body);
 514
 515     // If the <body> didn't have a custom style, then the root element might.
 516     Element* docElement = doc ? doc->documentElement() : 0;
 517     if (docElement && docElement->renderer() && docElement->renderer()->style().hasPseudoStyle(SCROLLBAR))
 518         return RenderScrollbar::createCustomScrollbar(this, orientation, docElement);
 519
 520     // If we have an owning iframe/frame element, then it can set the custom scrollbar also.
 521     RenderWidget* frameRenderer = frame().ownerRenderer();
 522     if (frameRenderer && frameRenderer->style().hasPseudoStyle(SCROLLBAR))
 523         return RenderScrollbar::createCustomScrollbar(this, orientation, 0, &frame());
 524
 525     // Nobody set a custom style, so we just use a native scrollbar.
 526     return ScrollView::createScrollbar(orientation);
 527 }
 528
 529 void FrameView::setContentsSize(const IntSize& size)
 530 {
 531     if (size == contentsSize())
 532         return;
 533
 534     m_deferSetNeedsLayouts++;
 535
 536     ScrollView::setContentsSize(size);
 537     ScrollView::contentsResized();
 538
 539     Page* page = frame().page();
 540     if (!page)
 541         return;
 542
 543     updateScrollableAreaSet();
 544
 545     page->chrome().contentsSizeChanged(&frame(), size); // Notify only.
 546
 547     ASSERT(m_deferSetNeedsLayouts);
 548     m_deferSetNeedsLayouts--;
 549
 550     if (!m_deferSetNeedsLayouts)
 551         m_setNeedsLayoutWasDeferred = false; // FIXME: Find a way to make the deferred layout actually happen.
 552 }
 553
 554 void FrameView::adjustViewSize()
 555 {
 556     RenderView* renderView = this->renderView();
 557     if (!renderView)
 558         return;
 559
 560     ASSERT(frame().view() == this);
 561
 562     const IntRect rect = renderView->documentRect();
 563     const IntSize& size = rect.size();
 564     ScrollView::setScrollOrigin(IntPoint(-rect.x(), -rect.y()), !frame().document()->printing(), size == contentsSize());
 565
 566     setContentsSize(size);
 567 }
 568
 569 void FrameView::applyOverflowToViewport(RenderElement* o, ScrollbarMode& hMode, ScrollbarMode& vMode)
 570 {
 571     // Handle the overflow:hidden/scroll case for the body/html elements.  WinIE treats
 572     // overflow:hidden and overflow:scroll on <body> as applying to the document's
 573     // scrollbars.  The CSS2.1 draft states that HTML UAs should use the <html> or <body> element and XML/XHTML UAs should
 574     // use the root element.
 575
 576     // To combat the inability to scroll on a page with overflow:hidden on the root when scaled, disregard hidden when
 577     // there is a frameScaleFactor that is greater than one on the main frame. Also disregard hidden if there is a
 578     // header or footer.
 579
 580     bool overrideHidden = frame().isMainFrame() && ((frame().frameScaleFactor() > 1) || headerHeight() || footerHeight());
 581
 582     EOverflow overflowX = o->style().overflowX();
 583     EOverflow overflowY = o->style().overflowY();
 584
 585     if (o->isSVGRoot()) {
 586         // FIXME: evaluate if we can allow overflow for these cases too.
 587         // Overflow is always hidden when stand-alone SVG documents are embedded.
 588         if (toRenderSVGRoot(o)->isEmbeddedThroughFrameContainingSVGDocument()) {
 589             overflowX = OHIDDEN;
 590             overflowY = OHIDDEN;
 591         }
 592     }
 593
 594     switch (overflowX) {
 595         case OHIDDEN:
 596             if (overrideHidden)
 597                 hMode = ScrollbarAuto;
 598             else
 599                 hMode = ScrollbarAlwaysOff;
 600             break;
 601         case OSCROLL:
 602             hMode = ScrollbarAlwaysOn;
 603             break;
 604         case OAUTO:
 605             hMode = ScrollbarAuto;
 606             break;
 607         default:
 608             // Don't set it at all.
 609             ;
 610     }
 611
 612      switch (overflowY) {
 613         case OHIDDEN:
 614             if (overrideHidden)
 615                 vMode = ScrollbarAuto;
 616             else
 617                 vMode = ScrollbarAlwaysOff;
 618             break;
 619         case OSCROLL:
 620             vMode = ScrollbarAlwaysOn;
 621             break;
 622         case OAUTO:
 623             vMode = ScrollbarAuto;
 624             break;
 625         default:
 626             // Don't set it at all. Values of OPAGEDX and OPAGEDY are handled by applyPaginationToViewPort().
 627             ;
 628     }
 629
 630     m_viewportRenderer = o;
 631 }
 632
 633 void FrameView::applyPaginationToViewport()
 634 {
 635     Document* document = frame().document();
 636     auto documentElement = document->documentElement();
 637     RenderElement* documentRenderer = documentElement ? documentElement->renderer() : nullptr;
 638     RenderElement* documentOrBodyRenderer = documentRenderer;
 639     auto body = document->body();
 640     if (body && body->renderer()) {
 641         if (body->hasTagName(bodyTag))
 642             documentOrBodyRenderer = documentRenderer->style().overflowX() == OVISIBLE && documentElement->hasTagName(htmlTag) ? body->renderer() : documentRenderer;
 643     }
 644
 645     Pagination pagination;
 646
 647     if (!documentOrBodyRenderer) {
 648         setPagination(pagination);
 649         return;
 650     }
 651
 652     EOverflow overflowY = documentOrBodyRenderer->style().overflowY();
 653     if (overflowY == OPAGEDX || overflowY == OPAGEDY) {
 654         pagination.mode = WebCore::paginationModeForRenderStyle(documentOrBodyRenderer->style());
 655         pagination.gap = static_cast<unsigned>(documentOrBodyRenderer->style().columnGap());
 656     }
 657
 658     setPagination(pagination);
 659 }
 660
 661 void FrameView::calculateScrollbarModesForLayout(ScrollbarMode& hMode, ScrollbarMode& vMode, ScrollbarModesCalculationStrategy strategy)
 662 {
 663     m_viewportRenderer = 0;
 664
 665     const HTMLFrameOwnerElement* owner = frame().ownerElement();
 666     if (owner && (owner->scrollingMode() == ScrollbarAlwaysOff)) {
 667         hMode = ScrollbarAlwaysOff;
 668         vMode = ScrollbarAlwaysOff;
 669         return;
 670     }
 671
 672     if (m_canHaveScrollbars || strategy == RulesFromWebContentOnly) {
 673         hMode = ScrollbarAuto;
 674         vMode = ScrollbarAuto;
 675     } else {
 676         hMode = ScrollbarAlwaysOff;
 677         vMode = ScrollbarAlwaysOff;
 678     }
 679
 680     if (!m_layoutRoot) {
 681         Document* document = frame().document();
 682         auto documentElement = document->documentElement();
 683         RenderElement* rootRenderer = documentElement ? documentElement->renderer() : nullptr;
 684         auto body = document->body();
 685         if (body && body->renderer()) {
 686             if (body->hasTagName(framesetTag) && !frameFlatteningEnabled()) {
 687                 vMode = ScrollbarAlwaysOff;
 688                 hMode = ScrollbarAlwaysOff;
 689             } else if (body->hasTagName(bodyTag)) {
 690                 // It's sufficient to just check the X overflow,
 691                 // since it's illegal to have visible in only one direction.
 692                 RenderElement* o = rootRenderer->style().overflowX() == OVISIBLE && document->documentElement()->hasTagName(htmlTag) ? body->renderer() : rootRenderer;
 693                 applyOverflowToViewport(o, hMode, vMode);
 694             }
 695         } else if (rootRenderer)
 696             applyOverflowToViewport(rootRenderer, hMode, vMode);
 697     }
 698 }
 699
 700 void FrameView::updateCompositingLayersAfterStyleChange()
 701 {
 702     RenderView* renderView = this->renderView();
 703     if (!renderView)
 704         return;
 705
 706     // If we expect to update compositing after an incipient layout, don't do so here.
 707     if (inPreLayoutStyleUpdate() || layoutPending() || renderView->needsLayout())
 708         return;
 709
 710     RenderLayerCompositor& compositor = renderView->compositor();
 711     // This call will make sure the cached hasAcceleratedCompositing is updated from the pref
 712     compositor.cacheAcceleratedCompositingFlags();
 713     compositor.updateCompositingLayers(CompositingUpdateAfterStyleChange);
 714 }
 715
 716 void FrameView::updateCompositingLayersAfterLayout()
 717 {
 718     RenderView* renderView = this->renderView();
 719     if (!renderView)
 720         return;
 721
 722     // This call will make sure the cached hasAcceleratedCompositing is updated from the pref
 723     renderView->compositor().cacheAcceleratedCompositingFlags();
 724     renderView->compositor().updateCompositingLayers(CompositingUpdateAfterLayout);
 725 }
 726
 727 void FrameView::clearBackingStores()
 728 {
 729     RenderView* renderView = this->renderView();
 730     if (!renderView)
 731         return;
 732
 733     RenderLayerCompositor& compositor = renderView->compositor();
 734     ASSERT(compositor.inCompositingMode());
 735     compositor.enableCompositingMode(false);
 736     compositor.clearBackingForAllLayers();
 737 }
 738
 739 void FrameView::restoreBackingStores()
 740 {
 741     RenderView* renderView = this->renderView();
 742     if (!renderView)
 743         return;
 744
 745     RenderLayerCompositor& compositor = renderView->compositor();
 746     compositor.enableCompositingMode(true);
 747     compositor.updateCompositingLayers(CompositingUpdateAfterLayout);
 748 }
 749
 750 GraphicsLayer* FrameView::layerForScrolling() const
 751 {
 752     RenderView* renderView = this->renderView();
 753     if (!renderView)
 754         return 0;
 755     return renderView->compositor().scrollLayer();
 756 }
 757
 758 GraphicsLayer* FrameView::layerForHorizontalScrollbar() const
 759 {
 760     RenderView* renderView = this->renderView();
 761     if (!renderView)
 762         return 0;
 763     return renderView->compositor().layerForHorizontalScrollbar();
 764 }
 765
 766 GraphicsLayer* FrameView::layerForVerticalScrollbar() const
 767 {
 768     RenderView* renderView = this->renderView();
 769     if (!renderView)
 770         return 0;
 771     return renderView->compositor().layerForVerticalScrollbar();
 772 }
 773
 774 GraphicsLayer* FrameView::layerForScrollCorner() const
 775 {
 776     RenderView* renderView = this->renderView();
 777     if (!renderView)
 778         return 0;
 779     return renderView->compositor().layerForScrollCorner();
 780 }
 781
 782 TiledBacking* FrameView::tiledBacking() const
 783 {
 784     RenderView* renderView = this->renderView();
 785     if (!renderView)
 786         return 0;
 787
 788     RenderLayerBacking* backing = renderView->layer()->backing();
 789     if (!backing)
 790         return 0;
 791
 792     return backing->graphicsLayer()->tiledBacking();
 793 }
 794
 795 uint64_t FrameView::scrollLayerID() const
 796 {
 797     RenderView* renderView = this->renderView();
 798     if (!renderView)
 799         return 0;
 800
 801     RenderLayerBacking* backing = renderView->layer()->backing();
 802     if (!backing)
 803         return 0;
 804
 805     return backing->scrollingNodeIDForRole(FrameScrollingNode);
 806 }
 807
 808 ScrollableArea* FrameView::scrollableAreaForScrollLayerID(uint64_t nodeID) const
 809 {
 810     RenderView* renderView = this->renderView();
 811     if (!renderView)
 812         return nullptr;
 813
 814     return renderView->compositor().scrollableAreaForScrollLayerID(nodeID);
 815 }
 816
 817 #if ENABLE(RUBBER_BANDING)
 818 GraphicsLayer* FrameView::layerForOverhangAreas() const
 819 {
 820     RenderView* renderView = this->renderView();
 821     if (!renderView)
 822         return 0;
 823     return renderView->compositor().layerForOverhangAreas();
 824 }
 825
 826 GraphicsLayer* FrameView::setWantsLayerForTopOverHangArea(bool wantsLayer) const
 827 {
 828     RenderView* renderView = this->renderView();
 829     if (!renderView)
 830         return 0;
 831
 832     return renderView->compositor().updateLayerForTopOverhangArea(wantsLayer);
 833 }
 834
 835 GraphicsLayer* FrameView::setWantsLayerForBottomOverHangArea(bool wantsLayer) const
 836 {
 837     RenderView* renderView = this->renderView();
 838     if (!renderView)
 839         return 0;
 840
 841     return renderView->compositor().updateLayerForBottomOverhangArea(wantsLayer);
 842 }
 843
 844 #endif // ENABLE(RUBBER_BANDING)
 845
 846 bool FrameView::flushCompositingStateForThisFrame(Frame* rootFrameForFlush)
 847 {
 848     RenderView* renderView = this->renderView();
 849     if (!renderView)
 850         return true; // We don't want to keep trying to update layers if we have no renderer.
 851
 852     ASSERT(frame().view() == this);
 853
 854     // If we sync compositing layers when a layout is pending, we may cause painting of compositing
 855     // layer content to occur before layout has happened, which will cause paintContents() to bail.
 856     if (needsLayout())
 857         return false;
 858
 859 #if PLATFORM(IOS)
 860     if (LegacyTileCache* tileCache = legacyTileCache())
 861         tileCache->doPendingRepaints();
 862 #endif
 863
 864     renderView->compositor().flushPendingLayerChanges(rootFrameForFlush == &frame());
 865
 866     return true;
 867 }
 868
 869 void FrameView::setNeedsOneShotDrawingSynchronization()
 870 {
 871     if (Page* page = frame().page())
 872         page->chrome().client().setNeedsOneShotDrawingSynchronization();
 873 }
 874
 875 GraphicsLayer* FrameView::graphicsLayerForPlatformWidget(PlatformWidget platformWidget)
 876 {
 877     // To find the Widget that corresponds with platformWidget we have to do a linear
 878     // search of our child widgets.
 879     Widget* foundWidget = nullptr;
 880     for (auto& widget : children()) {
 881         if (widget->platformWidget() != platformWidget)
 882             continue;
 883         foundWidget = widget.get();
 884         break;
 885     }
 886
 887     if (!foundWidget)
 888         return nullptr;
 889
 890     auto* renderWidget = RenderWidget::find(foundWidget);
 891     if (!renderWidget)
 892         return nullptr;
 893
 894     RenderLayer* widgetLayer = renderWidget->layer();
 895     if (!widgetLayer || !widgetLayer->isComposited())
 896         return nullptr;
 897
 898     return widgetLayer->backing()->parentForSublayers();
 899 }
 900
 901 void FrameView::scheduleLayerFlushAllowingThrottling()
 902 {
 903     RenderView* view = this->renderView();
 904     if (!view)
 905         return;
 906     view->compositor().scheduleLayerFlush(true /* canThrottle */);
 907 }
 908
 909 void FrameView::setHeaderHeight(int headerHeight)
 910 {
 911     if (frame().page())
 912         ASSERT(frame().isMainFrame());
 913     m_headerHeight = headerHeight;
 914
 915     if (RenderView* renderView = this->renderView())
 916         renderView->setNeedsLayout();
 917 }
 918
 919 void FrameView::setFooterHeight(int footerHeight)
 920 {
 921     if (frame().page())
 922         ASSERT(frame().isMainFrame());
 923     m_footerHeight = footerHeight;
 924
 925     if (RenderView* renderView = this->renderView())
 926         renderView->setNeedsLayout();
 927 }
 928
 929 float FrameView::topContentInset() const
 930 {
 931     if (!frame().isMainFrame())
 932         return 0;
 933
 934     Page* page = frame().page();
 935     return page ? page->topContentInset() : 0;
 936 }
 937
 938 void FrameView::topContentInsetDidChange()
 939 {
 940     RenderView* renderView = this->renderView();
 941     if (!renderView)
 942         return;
 943
 944     layout();
 945
 946     updateScrollbars(scrollOffset());
 947     if (renderView->usesCompositing())
 948         renderView->compositor().frameViewDidChangeSize();
 949
 950     if (TiledBacking* tiledBacking = this->tiledBacking())
 951         tiledBacking->setTopContentInset(topContentInset());
 952 }
 953
 954 bool FrameView::hasCompositedContent() const
 955 {
 956     if (RenderView* renderView = this->renderView())
 957         return renderView->compositor().inCompositingMode();
 958     return false;
 959 }
 960
 961 bool FrameView::hasCompositedContentIncludingDescendants() const
 962 {
 963     for (Frame* frame = m_frame.get(); frame; frame = frame->tree().traverseNext(m_frame.get())) {
 964         RenderView* renderView = frame->contentRenderer();
 965         if (RenderLayerCompositor* compositor = renderView ? &renderView->compositor() : 0) {
 966             if (compositor->inCompositingMode())
 967                 return true;
 968
 969             if (!RenderLayerCompositor::allowsIndependentlyCompositedFrames(this))
 970                 break;
 971         }
 972     }
 973     return false;
 974 }
 975
 976 bool FrameView::hasCompositingAncestor() const
 977 {
 978     for (Frame* frame = this->frame().tree().parent(); frame; frame = frame->tree().parent()) {
 979         if (FrameView* view = frame->view()) {
 980             if (view->hasCompositedContent())
 981                 return true;
 982         }
 983     }
 984     return false;
 985 }
 986
 987 // Sometimes (for plug-ins) we need to eagerly go into compositing mode.
 988 void FrameView::enterCompositingMode()
 989 {
 990     if (RenderView* renderView = this->renderView()) {
 991         renderView->compositor().enableCompositingMode();
 992         if (!needsLayout())
 993             renderView->compositor().scheduleCompositingLayerUpdate();
 994     }
 995 }
 996
 997 bool FrameView::isEnclosedInCompositingLayer() const
 998 {
 999     auto frameOwnerRenderer = frame().ownerRenderer();
1000     if (frameOwnerRenderer && frameOwnerRenderer->containerForRepaint())
1001         return true;
1002
1003     if (FrameView* parentView = parentFrameView())
1004         return parentView->isEnclosedInCompositingLayer();
1005     return false;
1006 }
1007
1008 bool FrameView::flushCompositingStateIncludingSubframes()
1009 {
1010     bool allFramesFlushed = flushCompositingStateForThisFrame(&frame());
1011
1012     for (Frame* child = frame().tree().firstChild(); child; child = child->tree().traverseNext(&frame())) {
1013         bool flushed = child->view()->flushCompositingStateForThisFrame(&frame());
1014         allFramesFlushed &= flushed;
1015     }
1016     return allFramesFlushed;
1017 }
1018
1019 bool FrameView::isSoftwareRenderable() const
1020 {
1021     RenderView* renderView = this->renderView();
1022     return !renderView || !renderView->compositor().has3DContent();
1023 }
1024
1025 void FrameView::didMoveOnscreen()
1026 {
1027     contentAreaDidShow();
1028 }
1029
1030 void FrameView::willMoveOffscreen()
1031 {
1032     contentAreaDidHide();
1033 }
1034
1035 void FrameView::setIsInWindow(bool isInWindow)
1036 {
1037     if (RenderView* renderView = this->renderView())
1038         renderView->setIsInWindow(isInWindow);
1039 }
1040
1041 RenderObject* FrameView::layoutRoot(bool onlyDuringLayout) const
1042 {
1043     return onlyDuringLayout && layoutPending() ? 0 : m_layoutRoot;
1044 }
1045
1046 inline void FrameView::forceLayoutParentViewIfNeeded()
1047 {
1048     RenderWidget* ownerRenderer = frame().ownerRenderer();
1049     if (!ownerRenderer)
1050         return;
1051
1052     RenderBox* contentBox = embeddedContentBox();
1053     if (!contentBox)
1054         return;
1055
1056     RenderSVGRoot* svgRoot = toRenderSVGRoot(contentBox);
1057     if (svgRoot->everHadLayout() && !svgRoot->needsLayout())
1058         return;
1059
1060     // If the embedded SVG document appears the first time, the ownerRenderer has already finished
1061     // layout without knowing about the existence of the embedded SVG document, because RenderReplaced
1062     // embeddedContentBox() returns 0, as long as the embedded document isn't loaded yet. Before
1063     // bothering to lay out the SVG document, mark the ownerRenderer needing layout and ask its
1064     // FrameView for a layout. After that the RenderEmbeddedObject (ownerRenderer) carries the
1065     // correct size, which RenderSVGRoot::computeReplacedLogicalWidth/Height rely on, when laying
1066     // out for the first time, or when the RenderSVGRoot size has changed dynamically (eg. via <script>).
1067     Ref<FrameView> frameView(ownerRenderer->view().frameView());
1068
1069     // Mark the owner renderer as needing layout.
1070     ownerRenderer->setNeedsLayoutAndPrefWidthsRecalc();
1071
1072     // Synchronously enter layout, to layout the view containing the host object/embed/iframe.
1073     frameView->layout();
1074 }
1075
1076 void FrameView::layout(bool allowSubtree)
1077 {
1078     if (isInLayout())
1079         return;
1080
1081     // Protect the view from being deleted during layout (in recalcStyle).
1082     Ref<FrameView> protect(*this);
1083
1084     // Many of the tasks performed during layout can cause this function to be re-entered,
1085     // so save the layout phase now and restore it on exit.
1086     TemporaryChange<LayoutPhase> layoutPhaseRestorer(m_layoutPhase, InPreLayout);
1087
1088     // Every scroll that happens during layout is programmatic.
1089     TemporaryChange<bool> changeInProgrammaticScroll(m_inProgrammaticScroll, true);
1090
1091     bool inChildFrameLayoutWithFrameFlattening = isInChildFrameWithFrameFlattening();
1092
1093     if (inChildFrameLayoutWithFrameFlattening) {
1094         startLayoutAtMainFrameViewIfNeeded(allowSubtree);
1095         RenderElement* root = m_layoutRoot ? m_layoutRoot : frame().document()->renderView();
1096         if (!root || !root->needsLayout())
1097             return;
1098     }
1099
1100 #if PLATFORM(IOS)
1101     if (updateFixedPositionLayoutRect())
1102         allowSubtree = false;
1103 #endif
1104
1105     m_layoutTimer.stop();
1106     m_delayedLayout = false;
1107     m_setNeedsLayoutWasDeferred = false;
1108
1109     // we shouldn't enter layout() while painting
1110     ASSERT(!isPainting());
1111     if (isPainting())
1112         return;
1113
1114     InspectorInstrumentationCookie cookie = InspectorInstrumentation::willLayout(&frame());
1115
1116     if (!allowSubtree && m_layoutRoot) {
1117         m_layoutRoot->markContainingBlocksForLayout(false);
1118         m_layoutRoot = 0;
1119     }
1120
1121     ASSERT(frame().view() == this);
1122     ASSERT(frame().document());
1123
1124     Document& document = *frame().document();
1125     ASSERT(!document.inPageCache());
1126
1127     bool subtree;
1128     RenderElement* root;
1129
1130     {
1131         TemporaryChange<bool> changeSchedulingEnabled(m_layoutSchedulingEnabled, false);
1132
1133         if (!m_nestedLayoutCount && !m_inSynchronousPostLayout && m_postLayoutTasksTimer.isActive() && !inChildFrameLayoutWithFrameFlattening) {
1134             // This is a new top-level layout. If there are any remaining tasks from the previous
1135             // layout, finish them now.
1136             TemporaryChange<bool> inSynchronousPostLayoutChange(m_inSynchronousPostLayout, true);
1137             performPostLayoutTasks();
1138         }
1139
1140         m_layoutPhase = InPreLayoutStyleUpdate;
1141
1142         // Viewport-dependent media queries may cause us to need completely different style information.
1143         StyleResolver* styleResolver = document.styleResolverIfExists();
1144         if (!styleResolver || styleResolver->hasMediaQueriesAffectedByViewportChange()) {
1145             document.styleResolverChanged(DeferRecalcStyle);
1146             // FIXME: This instrumentation event is not strictly accurate since cached media query results do not persist across StyleResolver rebuilds.
1147             InspectorInstrumentation::mediaQueryResultChanged(&document);
1148         } else
1149             document.evaluateMediaQueryList();
1150
1151         // If there is any pagination to apply, it will affect the RenderView's style, so we should
1152         // take care of that now.
1153         applyPaginationToViewport();
1154
1155         // Always ensure our style info is up-to-date. This can happen in situations where
1156         // the layout beats any sort of style recalc update that needs to occur.
1157         document.updateStyleIfNeeded();
1158         m_layoutPhase = InPreLayout;
1159
1160         subtree = m_layoutRoot;
1161
1162         // If there is only one ref to this view left, then its going to be destroyed as soon as we exit,
1163         // so there's no point to continuing to layout
1164         if (hasOneRef())
1165             return;
1166
1167         root = subtree ? m_layoutRoot : document.renderView();
1168         if (!root) {
1169             // FIXME: Do we need to set m_size here?
1170             return;
1171         }
1172
1173         // Close block here so we can set up the font cache purge preventer, which we will still
1174         // want in scope even after we want m_layoutSchedulingEnabled to be restored again.
1175         // The next block sets m_layoutSchedulingEnabled back to false once again.
1176     }
1177
1178     FontCachePurgePreventer fontCachePurgePreventer;
1179     RenderLayer* layer;
1180
1181     ++m_nestedLayoutCount;
1182
1183     {
1184         TemporaryChange<bool> changeSchedulingEnabled(m_layoutSchedulingEnabled, false);
1185
1186         if (!m_layoutRoot) {
1187             HTMLElement* body = document.body();
1188             if (body && body->renderer()) {
1189                 if (body->hasTagName(framesetTag) && !frameFlatteningEnabled()) {
1190                     body->renderer()->setChildNeedsLayout();
1191                 } else if (body->hasTagName(bodyTag)) {
1192                     if (!m_firstLayout && m_size.height() != layoutHeight() && body->renderer()->enclosingBox().stretchesToViewport())
1193                         body->renderer()->setChildNeedsLayout();
1194                 }
1195             }
1196
1197 #ifdef INSTRUMENT_LAYOUT_SCHEDULING
1198             if (m_firstLayout && !frame().ownerElement())
1199                 printf("Elapsed time before first layout: %lld\n", document.elapsedTime().count());
1200 #endif
1201         }
1202
1203         autoSizeIfEnabled();
1204
1205         m_needsFullRepaint = !subtree && (m_firstLayout || toRenderView(*root).printing());
1206
1207         if (!subtree) {
1208             ScrollbarMode hMode;
1209             ScrollbarMode vMode;
1210             calculateScrollbarModesForLayout(hMode, vMode);
1211
1212             if (m_firstLayout || (hMode != horizontalScrollbarMode() || vMode != verticalScrollbarMode())) {
1213                 if (m_firstLayout) {
1214                     setScrollbarsSuppressed(true);
1215
1216                     m_firstLayout = false;
1217                     m_firstLayoutCallbackPending = true;
1218                     m_lastViewportSize = sizeForResizeEvent();
1219                     m_lastZoomFactor = root->style().zoom();
1220
1221                     // Set the initial vMode to AlwaysOn if we're auto.
1222                     if (vMode == ScrollbarAuto)
1223                         setVerticalScrollbarMode(ScrollbarAlwaysOn); // This causes a vertical scrollbar to appear.
1224                     // Set the initial hMode to AlwaysOff if we're auto.
1225                     if (hMode == ScrollbarAuto)
1226                         setHorizontalScrollbarMode(ScrollbarAlwaysOff); // This causes a horizontal scrollbar to disappear.
1227
1228                     setScrollbarModes(hMode, vMode);
1229                     setScrollbarsSuppressed(false, true);
1230                 } else
1231                     setScrollbarModes(hMode, vMode);
1232             }
1233
1234             LayoutSize oldSize = m_size;
1235
1236             m_size = layoutSize();
1237
1238             if (oldSize != m_size) {
1239                 m_needsFullRepaint = true;
1240                 if (!m_firstLayout) {
1241                     RenderBox* rootRenderer = document.documentElement() ? document.documentElement()->renderBox() : 0;
1242                     RenderBox* bodyRenderer = rootRenderer && document.body() ? document.body()->renderBox() : 0;
1243                     if (bodyRenderer && bodyRenderer->stretchesToViewport())
1244                         bodyRenderer->setChildNeedsLayout();
1245                     else if (rootRenderer && rootRenderer->stretchesToViewport())
1246                         rootRenderer->setChildNeedsLayout();
1247
1248                     document.updateViewportUnitsOnResize();
1249                 }
1250             }
1251
1252             m_layoutPhase = InPreLayout;
1253         }
1254
1255         layer = root->enclosingLayer();
1256
1257         bool disableLayoutState = false;
1258         if (subtree) {
1259             disableLayoutState = root->view().shouldDisableLayoutStateForSubtree(root);
1260             root->view().pushLayoutState(*root);
1261         }
1262         LayoutStateDisabler layoutStateDisabler(disableLayoutState ? &root->view() : 0);
1263         RenderView::RepaintRegionAccumulator repaintRegionAccumulator(&root->view());
1264
1265         ASSERT(m_layoutPhase == InPreLayout);
1266         m_layoutPhase = InLayout;
1267
1268         forceLayoutParentViewIfNeeded();
1269
1270         ASSERT(m_layoutPhase == InLayout);
1271
1272         root->layout();
1273 #if ENABLE(IOS_TEXT_AUTOSIZING)
1274         float minZoomFontSize = frame().settings().minimumZoomFontSize();
1275         float visWidth = frame().page()->textAutosizingWidth();
1276         if (minZoomFontSize && visWidth && !root->view().printing()) {
1277             root->adjustComputedFontSizesOnBlocks(minZoomFontSize, visWidth);
1278             bool needsLayout = root->needsLayout();
1279             if (needsLayout)
1280                 root->layout();
1281         }
1282 #endif
1283 #if ENABLE(TEXT_AUTOSIZING)
1284         if (document.textAutosizer()->processSubtree(root) && root->needsLayout())
1285             root->layout();
1286 #endif
1287
1288         ASSERT(m_layoutPhase == InLayout);
1289
1290         if (subtree)
1291             root->view().popLayoutState(*root);
1292
1293         m_layoutRoot = 0;
1294
1295         // Close block here to end the scope of changeSchedulingEnabled and layoutStateDisabler.
1296     }
1297
1298     m_layoutPhase = InViewSizeAdjust;
1299
1300     bool neededFullRepaint = m_needsFullRepaint;
1301
1302     if (!subtree && !toRenderView(*root).printing())
1303         adjustViewSize();
1304
1305     m_layoutPhase = InPostLayout;
1306
1307     m_needsFullRepaint = neededFullRepaint;
1308
1309     // Now update the positions of all layers.
1310     if (m_needsFullRepaint)
1311         root->view().repaintRootContents();
1312
1313     layer->updateLayerPositionsAfterLayout(renderView()->layer(), updateLayerPositionFlags(layer, subtree, m_needsFullRepaint));
1314
1315     updateCompositingLayersAfterLayout();
1316
1317     m_layoutCount++;
1318
1319 #if PLATFORM(COCOA) || PLATFORM(WIN) || PLATFORM(GTK) || PLATFORM(EFL)
1320     if (AXObjectCache* cache = root->document().existingAXObjectCache())
1321         cache->postNotification(root, AXObjectCache::AXLayoutComplete);
1322 #endif
1323
1324 #if ENABLE(DASHBOARD_SUPPORT)
1325     updateAnnotatedRegions();
1326 #endif
1327
1328 #if ENABLE(IOS_TOUCH_EVENTS)
1329     document.dirtyTouchEventRects();
1330 #endif
1331
1332     ASSERT(!root->needsLayout());
1333
1334     updateCanBlitOnScrollRecursively();
1335
1336     if (document.hasListenerType(Document::OVERFLOWCHANGED_LISTENER))
1337         updateOverflowStatus(layoutWidth() < contentsWidth(), layoutHeight() < contentsHeight());
1338
1339     if (!m_postLayoutTasksTimer.isActive()) {
1340         if (!m_inSynchronousPostLayout) {
1341             if (inChildFrameLayoutWithFrameFlattening)
1342                 updateWidgetPositions();
1343             else {
1344                 TemporaryChange<bool> inSynchronousPostLayoutChange(m_inSynchronousPostLayout, true);
1345                 performPostLayoutTasks(); // Calls resumeScheduledEvents().
1346             }
1347         }
1348
1349         if (!m_postLayoutTasksTimer.isActive() && (needsLayout() || m_inSynchronousPostLayout || inChildFrameLayoutWithFrameFlattening)) {
1350             // If we need layout or are already in a synchronous call to postLayoutTasks(),
1351             // defer widget updates and event dispatch until after we return. postLayoutTasks()
1352             // can make us need to update again, and we can get stuck in a nasty cycle unless
1353             // we call it through the timer here.
1354             m_postLayoutTasksTimer.startOneShot(0);
1355             if (needsLayout())
1356                 layout();
1357         }
1358     }
1359
1360     InspectorInstrumentation::didLayout(cookie, root);
1361
1362     --m_nestedLayoutCount;
1363 }
1364
1365 RenderBox* FrameView::embeddedContentBox() const
1366 {
1367     RenderView* renderView = this->renderView();
1368     if (!renderView)
1369         return nullptr;
1370
1371     RenderObject* firstChild = renderView->firstChild();
1372     if (!firstChild || !firstChild->isBox())
1373         return nullptr;
1374
1375     // Curently only embedded SVG documents participate in the size-negotiation logic.
1376     if (toRenderBox(firstChild)->isSVGRoot())
1377         return toRenderBox(firstChild);
1378
1379     return nullptr;
1380 }
1381
1382 void FrameView::addEmbeddedObjectToUpdate(RenderEmbeddedObject& embeddedObject)
1383 {
1384     if (!m_embeddedObjectsToUpdate)
1385         m_embeddedObjectsToUpdate = std::make_unique<ListHashSet<RenderEmbeddedObject*>>();
1386
1387     HTMLFrameOwnerElement& element = embeddedObject.frameOwnerElement();
1388     if (isHTMLObjectElement(element) || isHTMLEmbedElement(element)) {
1389         // Tell the DOM element that it needs a widget update.
1390         HTMLPlugInImageElement& pluginElement = toHTMLPlugInImageElement(element);
1391         if (!pluginElement.needsCheckForSizeChange())
1392             pluginElement.setNeedsWidgetUpdate(true);
1393     }
1394
1395     m_embeddedObjectsToUpdate->add(&embeddedObject);
1396 }
1397
1398 void FrameView::removeEmbeddedObjectToUpdate(RenderEmbeddedObject& embeddedObject)
1399 {
1400     if (!m_embeddedObjectsToUpdate)
1401         return;
1402
1403     m_embeddedObjectsToUpdate->remove(&embeddedObject);
1404 }
1405
1406 void FrameView::setMediaType(const String& mediaType)
1407 {
1408     m_mediaType = mediaType;
1409 }
1410
1411 String FrameView::mediaType() const
1412 {
1413     // See if we have an override type.
1414     String overrideType = frame().loader().client().overrideMediaType();
1415     InspectorInstrumentation::applyEmulatedMedia(&frame(), &overrideType);
1416     if (!overrideType.isNull())
1417         return overrideType;
1418     return m_mediaType;
1419 }
1420
1421 void FrameView::adjustMediaTypeForPrinting(bool printing)
1422 {
1423     if (printing) {
1424         if (m_mediaTypeWhenNotPrinting.isNull())
1425             m_mediaTypeWhenNotPrinting = mediaType();
1426             setMediaType("print");
1427     } else {
1428         if (!m_mediaTypeWhenNotPrinting.isNull())
1429             setMediaType(m_mediaTypeWhenNotPrinting);
1430         m_mediaTypeWhenNotPrinting = String();
1431     }
1432 }
1433
1434 bool FrameView::useSlowRepaints(bool considerOverlap) const
1435 {
1436     bool mustBeSlow = hasSlowRepaintObjects() || (platformWidget() && hasViewportConstrainedObjects());
1437
1438     // FIXME: WidgetMac.mm makes the assumption that useSlowRepaints ==
1439     // m_contentIsOpaque, so don't take the fast path for composited layers
1440     // if they are a platform widget in order to get painting correctness
1441     // for transparent layers. See the comment in WidgetMac::paint.
1442     if (contentsInCompositedLayer() && !platformWidget())
1443         return mustBeSlow;
1444
1445     bool isOverlapped = m_isOverlapped && considerOverlap;
1446
1447     if (mustBeSlow || m_cannotBlitToWindow || isOverlapped || !m_contentIsOpaque)
1448         return true;
1449
1450     if (FrameView* parentView = parentFrameView())
1451         return parentView->useSlowRepaints(considerOverlap);
1452
1453     return false;
1454 }
1455
1456 bool FrameView::useSlowRepaintsIfNotOverlapped() const
1457 {
1458     return useSlowRepaints(false);
1459 }
1460
1461 void FrameView::updateCanBlitOnScrollRecursively()
1462 {
1463     for (Frame* frame = m_frame.get(); frame; frame = frame->tree().traverseNext(m_frame.get())) {
1464         if (FrameView* view = frame->view())
1465             view->setCanBlitOnScroll(!view->useSlowRepaints());
1466     }
1467 }
1468
1469 bool FrameView::contentsInCompositedLayer() const
1470 {
1471     RenderView* renderView = this->renderView();
1472     if (renderView && renderView->isComposited()) {
1473         GraphicsLayer* layer = renderView->layer()->backing()->graphicsLayer();
1474         if (layer && layer->drawsContent())
1475             return true;
1476     }
1477
1478     return false;
1479 }
1480
1481 void FrameView::setCannotBlitToWindow()
1482 {
1483     m_cannotBlitToWindow = true;
1484     updateCanBlitOnScrollRecursively();
1485 }
1486
1487 void FrameView::addSlowRepaintObject(RenderElement* o)
1488 {
1489     bool hadSlowRepaintObjects = hasSlowRepaintObjects();
1490
1491     if (!m_slowRepaintObjects)
1492         m_slowRepaintObjects = std::make_unique<HashSet<RenderElement*>>();
1493
1494     m_slowRepaintObjects->add(o);
1495
1496     if (!hadSlowRepaintObjects) {
1497         updateCanBlitOnScrollRecursively();
1498
1499         if (Page* page = frame().page()) {
1500             if (ScrollingCoordinator* scrollingCoordinator = page->scrollingCoordinator())
1501                 scrollingCoordinator->frameViewHasSlowRepaintObjectsDidChange(this);
1502         }
1503     }
1504 }
1505
1506 void FrameView::removeSlowRepaintObject(RenderElement* o)
1507 {
1508     if (!m_slowRepaintObjects)
1509         return;
1510
1511     m_slowRepaintObjects->remove(o);
1512     if (m_slowRepaintObjects->isEmpty()) {
1513         m_slowRepaintObjects = nullptr;
1514         updateCanBlitOnScrollRecursively();
1515
1516         if (Page* page = frame().page()) {
1517             if (ScrollingCoordinator* scrollingCoordinator = page->scrollingCoordinator())
1518                 scrollingCoordinator->frameViewHasSlowRepaintObjectsDidChange(this);
1519         }
1520     }
1521 }
1522
1523 void FrameView::addViewportConstrainedObject(RenderElement* object)
1524 {
1525     if (!m_viewportConstrainedObjects)
1526         m_viewportConstrainedObjects = std::make_unique<ViewportConstrainedObjectSet>();
1527
1528     if (!m_viewportConstrainedObjects->contains(object)) {
1529         m_viewportConstrainedObjects->add(object);
1530         if (platformWidget())
1531             updateCanBlitOnScrollRecursively();
1532
1533         if (Page* page = frame().page()) {
1534             if (ScrollingCoordinator* scrollingCoordinator = page->scrollingCoordinator())
1535                 scrollingCoordinator->frameViewFixedObjectsDidChange(this);
1536         }
1537     }
1538 }
1539
1540 void FrameView::removeViewportConstrainedObject(RenderElement* object)
1541 {
1542     if (m_viewportConstrainedObjects && m_viewportConstrainedObjects->remove(object)) {
1543         if (Page* page = frame().page()) {
1544             if (ScrollingCoordinator* scrollingCoordinator = page->scrollingCoordinator())
1545                 scrollingCoordinator->frameViewFixedObjectsDidChange(this);
1546         }
1547
1548         // FIXME: In addFixedObject() we only call this if there's a platform widget,
1549         // why isn't the same check being made here?
1550         updateCanBlitOnScrollRecursively();
1551     }
1552 }
1553
1554 LayoutRect FrameView::viewportConstrainedVisibleContentRect() const
1555 {
1556 #if PLATFORM(IOS)
1557     if (useCustomFixedPositionLayoutRect())
1558         return customFixedPositionLayoutRect();
1559 #endif
1560     LayoutRect viewportRect = visibleContentRect();
1561
1562     viewportRect.setLocation(toLayoutPoint(scrollOffsetForFixedPosition()));
1563     return viewportRect;
1564 }
1565
1566 LayoutSize FrameView::scrollOffsetForFixedPosition(const LayoutRect& visibleContentRect, const LayoutSize& totalContentsSize, const LayoutPoint& scrollPosition, const LayoutPoint& scrollOrigin, float frameScaleFactor, bool fixedElementsLayoutRelativeToFrame, ScrollBehaviorForFixedElements behaviorForFixed, int headerHeight, int footerHeight)
1567 {
1568     LayoutPoint position;
1569     if (behaviorForFixed == StickToDocumentBounds)
1570         position = ScrollableArea::constrainScrollPositionForOverhang(visibleContentRect, totalContentsSize, scrollPosition, scrollOrigin, headerHeight, footerHeight);
1571     else {
1572         position = scrollPosition;
1573         position.setY(position.y() - headerHeight);
1574     }
1575
1576     LayoutSize maxSize = totalContentsSize - visibleContentRect.size();
1577
1578     float dragFactorX = (fixedElementsLayoutRelativeToFrame || !maxSize.width()) ? 1 : (totalContentsSize.width() - visibleContentRect.width() * frameScaleFactor) / maxSize.width();
1579     float dragFactorY = (fixedElementsLayoutRelativeToFrame || !maxSize.height()) ? 1 : (totalContentsSize.height() - visibleContentRect.height() * frameScaleFactor) / maxSize.height();
1580
1581     return LayoutSize(position.x() * dragFactorX / frameScaleFactor, position.y() * dragFactorY / frameScaleFactor);
1582 }
1583
1584 LayoutSize FrameView::scrollOffsetForFixedPosition() const
1585 {
1586     IntRect visibleContentRect = this->visibleContentRect();
1587     IntSize totalContentsSize = this->totalContentsSize();
1588     IntPoint scrollPosition = this->scrollPosition();
1589     IntPoint scrollOrigin = this->scrollOrigin();
1590     float frameScaleFactor = frame().frameScaleFactor();
1591     ScrollBehaviorForFixedElements behaviorForFixed = scrollBehaviorForFixedElements();
1592     return scrollOffsetForFixedPosition(visibleContentRect, totalContentsSize, scrollPosition, scrollOrigin, frameScaleFactor, fixedElementsLayoutRelativeToFrame(), behaviorForFixed, headerHeight(), footerHeight());
1593 }
1594
1595 float FrameView::yPositionForInsetClipLayer(const FloatPoint& scrollPosition, float topContentInset)
1596 {
1597     if (!topContentInset)
1598         return 0;
1599
1600     // The insetClipLayer should not move for negative scroll values.
1601     float scrollY = std::max<float>(0, scrollPosition.y());
1602
1603     if (scrollY >= topContentInset)
1604         return 0;
1605
1606     return topContentInset - scrollY;
1607 }
1608
1609 float FrameView::yPositionForHeaderLayer(const FloatPoint& scrollPosition, float topContentInset)
1610 {
1611     if (!topContentInset)
1612         return 0;
1613
1614     float scrollY = std::max<float>(0, scrollPosition.y());
1615
1616     if (scrollY >= topContentInset)
1617         return topContentInset;
1618
1619     return scrollY;
1620 }
1621
1622 float FrameView::yPositionForRootContentLayer(const FloatPoint& scrollPosition, float topContentInset, float headerHeight)
1623 {
1624     return yPositionForHeaderLayer(scrollPosition, topContentInset) + headerHeight;
1625 }
1626
1627 float FrameView::yPositionForFooterLayer(const FloatPoint& scrollPosition, float topContentInset, float totalContentsHeight, float footerHeight)
1628 {
1629     return yPositionForHeaderLayer(scrollPosition, topContentInset) + totalContentsHeight - footerHeight;
1630 }
1631
1632 #if PLATFORM(IOS)
1633 LayoutRect FrameView::rectForViewportConstrainedObjects(const LayoutRect& visibleContentRect, const LayoutSize& totalContentsSize, float frameScaleFactor, bool fixedElementsLayoutRelativeToFrame, ScrollBehaviorForFixedElements scrollBehavior)
1634 {
1635     if (fixedElementsLayoutRelativeToFrame)
1636         return visibleContentRect;
1637
1638     // We impose an lower limit on the size (so an upper limit on the scale) of
1639     // the rect used to position fixed objects so that they don't crowd into the
1640     // center of the screen at larger scales.
1641     const float constraintThresholdScale = 1.2;
1642
1643     float maxPostionedObjectsRectScale = std::min(frameScaleFactor, constraintThresholdScale);
1644
1645     LayoutRect viewportConstrainedObjectsRect = visibleContentRect;
1646
1647     if (frameScaleFactor > constraintThresholdScale) {
1648         FloatRect contentRect(FloatPoint(), totalContentsSize);
1649         FloatRect viewportRect = visibleContentRect;
1650
1651         // Scale the rect up from a point that is relative to its position in the viewport.
1652         FloatSize sizeDelta = contentRect.size() - viewportRect.size();
1653
1654         FloatPoint scaleOrigin;
1655         scaleOrigin.setX(contentRect.x() + sizeDelta.width() > 0 ? contentRect.width() * (viewportRect.x() - contentRect.x()) / sizeDelta.width() : 0);
1656         scaleOrigin.setY(contentRect.y() + sizeDelta.height() > 0 ? contentRect.height() * (viewportRect.y() - contentRect.y()) / sizeDelta.height() : 0);
1657
1658         AffineTransform rescaleTransform = AffineTransform::translation(scaleOrigin.x(), scaleOrigin.y());
1659         rescaleTransform.scale(frameScaleFactor / maxPostionedObjectsRectScale, frameScaleFactor / maxPostionedObjectsRectScale);
1660         rescaleTransform = CGAffineTransformTranslate(rescaleTransform, -scaleOrigin.x(), -scaleOrigin.y());
1661
1662         viewportConstrainedObjectsRect = enclosingLayoutRect(rescaleTransform.mapRect(visibleContentRect));
1663     }
1664
1665     if (scrollBehavior == StickToDocumentBounds) {
1666         LayoutRect documentBounds(LayoutPoint(), totalContentsSize);
1667         viewportConstrainedObjectsRect.intersect(documentBounds);
1668     }
1669
1670     return viewportConstrainedObjectsRect;
1671 }
1672
1673 LayoutRect FrameView::viewportConstrainedObjectsRect() const
1674 {
1675     return rectForViewportConstrainedObjects(visibleContentRect(), totalContentsSize(), frame().frameScaleFactor(), fixedElementsLayoutRelativeToFrame(), scrollBehaviorForFixedElements());
1676 }
1677 #endif
1678
1679 IntPoint FrameView::minimumScrollPosition() const
1680 {
1681     IntPoint minimumPosition(ScrollView::minimumScrollPosition());
1682
1683     if (frame().isMainFrame() && m_scrollPinningBehavior == PinToBottom)
1684         minimumPosition.setY(maximumScrollPosition().y());
1685
1686     return minimumPosition;
1687 }
1688
1689 IntPoint FrameView::maximumScrollPosition() const
1690 {
1691     IntPoint maximumOffset(contentsWidth() - visibleWidth() - scrollOrigin().x(), totalContentsSize().height() - visibleHeight() - scrollOrigin().y());
1692
1693     maximumOffset.clampNegativeToZero();
1694
1695     if (frame().isMainFrame() && m_scrollPinningBehavior == PinToTop)
1696         maximumOffset.setY(minimumScrollPosition().y());
1697
1698     return maximumOffset;
1699 }
1700
1701 bool FrameView::fixedElementsLayoutRelativeToFrame() const
1702 {
1703     return frame().settings().fixedElementsLayoutRelativeToFrame();
1704 }
1705
1706 IntPoint FrameView::lastKnownMousePosition() const
1707 {
1708     return frame().eventHandler().lastKnownMousePosition();
1709 }
1710
1711 bool FrameView::isHandlingWheelEvent() const
1712 {
1713     return frame().eventHandler().isHandlingWheelEvent();
1714 }
1715
1716 bool FrameView::shouldSetCursor() const
1717 {
1718     Page* page = frame().page();
1719     return page && page->isVisible() && page->focusController().isActive();
1720 }
1721
1722 bool FrameView::scrollContentsFastPath(const IntSize& scrollDelta, const IntRect& rectToScroll, const IntRect& clipRect)
1723 {
1724     if (!m_viewportConstrainedObjects || m_viewportConstrainedObjects->isEmpty()) {
1725         hostWindow()->scroll(scrollDelta, rectToScroll, clipRect);
1726         return true;
1727     }
1728
1729     const bool isCompositedContentLayer = contentsInCompositedLayer();
1730
1731     // Get the rects of the fixed objects visible in the rectToScroll
1732     Region regionToUpdate;
1733     for (auto& renderer : *m_viewportConstrainedObjects) {
1734         if (!renderer->style().hasViewportConstrainedPosition())
1735             continue;
1736         if (renderer->isComposited())
1737             continue;
1738
1739         // Fixed items should always have layers.
1740         ASSERT(renderer->hasLayer());
1741         RenderLayer* layer = toRenderBoxModelObject(renderer)->layer();
1742
1743         if (layer->viewportConstrainedNotCompositedReason() == RenderLayer::NotCompositedForBoundsOutOfView
1744             || layer->viewportConstrainedNotCompositedReason() == RenderLayer::NotCompositedForNoVisibleContent) {
1745             // Don't invalidate for invisible fixed layers.
1746             continue;
1747         }
1748
1749 #if ENABLE(CSS_FILTERS)
1750         if (layer->hasAncestorWithFilterOutsets()) {
1751             // If the fixed layer has a blur/drop-shadow filter applied on at least one of its parents, we cannot
1752             // scroll using the fast path, otherwise the outsets of the filter will be moved around the page.
1753             return false;
1754         }
1755 #endif
1756         IntRect updateRect = pixelSnappedIntRect(layer->repaintRectIncludingNonCompositingDescendants());
1757         updateRect = contentsToRootView(updateRect);
1758         if (!isCompositedContentLayer && clipsRepaints())
1759             updateRect.intersect(rectToScroll);
1760         if (!updateRect.isEmpty())
1761             regionToUpdate.unite(updateRect);
1762     }
1763
1764     // 1) scroll
1765     hostWindow()->scroll(scrollDelta, rectToScroll, clipRect);
1766
1767     // 2) update the area of fixed objects that has been invalidated
1768     Vector<IntRect> subRectsToUpdate = regionToUpdate.rects();
1769     size_t viewportConstrainedObjectsCount = subRectsToUpdate.size();
1770     for (size_t i = 0; i < viewportConstrainedObjectsCount; ++i) {
1771         IntRect updateRect = subRectsToUpdate[i];
1772         IntRect scrolledRect = updateRect;
1773         scrolledRect.move(scrollDelta);
1774         updateRect.unite(scrolledRect);
1775         if (isCompositedContentLayer) {
1776             updateRect = rootViewToContents(updateRect);
1777             ASSERT(renderView());
1778             renderView()->layer()->setBackingNeedsRepaintInRect(updateRect);
1779             continue;
1780         }
1781         if (clipsRepaints())
1782             updateRect.intersect(rectToScroll);
1783         hostWindow()->invalidateContentsAndRootView(updateRect);
1784     }
1785
1786     return true;
1787 }
1788
1789 void FrameView::scrollContentsSlowPath(const IntRect& updateRect)
1790 {
1791     if (contentsInCompositedLayer()) {
1792         // FIXME: respect paintsEntireContents()?
1793         IntRect updateRect = visibleContentRect(LegacyIOSDocumentVisibleRect);
1794
1795         // Make sure to "apply" the scale factor here since we're converting from frame view
1796         // coordinates to layer backing coordinates.
1797         updateRect.scale(1 / frame().frameScaleFactor());
1798
1799         ASSERT(renderView());
1800         renderView()->layer()->setBackingNeedsRepaintInRect(updateRect, GraphicsLayer::DoNotClipToLayer);
1801     }
1802
1803     repaintSlowRepaintObjects();
1804
1805     if (RenderWidget* frameRenderer = frame().ownerRenderer()) {
1806         if (isEnclosedInCompositingLayer()) {
1807             LayoutRect rect(frameRenderer->borderLeft() + frameRenderer->paddingLeft(),
1808                             frameRenderer->borderTop() + frameRenderer->paddingTop(),
1809                             visibleWidth(), visibleHeight());
1810             frameRenderer->repaintRectangle(rect);
1811             return;
1812         }
1813     }
1814
1815     ScrollView::scrollContentsSlowPath(updateRect);
1816 }
1817
1818 void FrameView::repaintSlowRepaintObjects()
1819 {
1820     if (!m_slowRepaintObjects)
1821         return;
1822
1823     // Renderers with fixed backgrounds may be in compositing layers, so we need to explicitly
1824     // repaint them after scrolling.
1825     for (auto& renderer : *m_slowRepaintObjects)
1826         renderer->repaintSlowRepaintObject();
1827 }
1828
1829 // Note that this gets called at painting time.
1830 void FrameView::setIsOverlapped(bool isOverlapped)
1831 {
1832     if (isOverlapped == m_isOverlapped)
1833         return;
1834
1835     m_isOverlapped = isOverlapped;
1836     updateCanBlitOnScrollRecursively();
1837
1838     if (hasCompositedContentIncludingDescendants()) {
1839         // Overlap can affect compositing tests, so if it changes, we need to trigger
1840         // a layer update in the parent document.
1841         if (Frame* parentFrame = frame().tree().parent()) {
1842             if (RenderView* parentView = parentFrame->contentRenderer()) {
1843                 RenderLayerCompositor& compositor = parentView->compositor();
1844                 compositor.setCompositingLayersNeedRebuild();
1845                 compositor.scheduleCompositingLayerUpdate();
1846             }
1847         }
1848
1849         if (RenderLayerCompositor::allowsIndependentlyCompositedFrames(this)) {
1850             // We also need to trigger reevaluation for this and all descendant frames,
1851             // since a frame uses compositing if any ancestor is compositing.
1852             for (Frame* frame = m_frame.get(); frame; frame = frame->tree().traverseNext(m_frame.get())) {
1853                 if (RenderView* view = frame->contentRenderer()) {
1854                     RenderLayerCompositor& compositor = view->compositor();
1855                     compositor.setCompositingLayersNeedRebuild();
1856                     compositor.scheduleCompositingLayerUpdate();
1857                 }
1858             }
1859         }
1860     }
1861 }
1862
1863 bool FrameView::isOverlappedIncludingAncestors() const
1864 {
1865     if (isOverlapped())
1866         return true;
1867
1868     if (FrameView* parentView = parentFrameView()) {
1869         if (parentView->isOverlapped())
1870             return true;
1871     }
1872
1873     return false;
1874 }
1875
1876 void FrameView::setContentIsOpaque(bool contentIsOpaque)
1877 {
1878     if (contentIsOpaque == m_contentIsOpaque)
1879         return;
1880
1881     m_contentIsOpaque = contentIsOpaque;
1882     updateCanBlitOnScrollRecursively();
1883 }
1884
1885 void FrameView::restoreScrollbar()
1886 {
1887     setScrollbarsSuppressed(false);
1888 }
1889
1890 bool FrameView::scrollToFragment(const URL& url)
1891 {
1892     // If our URL has no ref, then we have no place we need to jump to.
1893     // OTOH If CSS target was set previously, we want to set it to 0, recalc
1894     // and possibly repaint because :target pseudo class may have been
1895     // set (see bug 11321).
1896     if (!url.hasFragmentIdentifier() && !frame().document()->cssTarget())
1897         return false;
1898
1899     String fragmentIdentifier = url.fragmentIdentifier();
1900     if (scrollToAnchor(fragmentIdentifier))
1901         return true;
1902
1903     // Try again after decoding the ref, based on the document's encoding.
1904     if (TextResourceDecoder* decoder = frame().document()->decoder())
1905         return scrollToAnchor(decodeURLEscapeSequences(fragmentIdentifier, decoder->encoding()));
1906
1907     return false;
1908 }
1909
1910 bool FrameView::scrollToAnchor(const String& name)
1911 {
1912     ASSERT(frame().document());
1913
1914     if (!frame().document()->haveStylesheetsLoaded()) {
1915         frame().document()->setGotoAnchorNeededAfterStylesheetsLoad(true);
1916         return false;
1917     }
1918
1919     frame().document()->setGotoAnchorNeededAfterStylesheetsLoad(false);
1920
1921     Element* anchorElement = frame().document()->findAnchor(name);
1922
1923     // Setting to null will clear the current target.
1924     frame().document()->setCSSTarget(anchorElement);
1925
1926     if (frame().document()->isSVGDocument()) {
1927         if (SVGSVGElement* svg = toSVGDocument(frame().document())->rootElement()) {
1928             svg->setupInitialView(name, anchorElement);
1929             if (!anchorElement)
1930                 return true;
1931         }
1932     }
1933
1934     // Implement the rule that "" and "top" both mean top of page as in other browsers.
1935     if (!anchorElement && !(name.isEmpty() || equalIgnoringCase(name, "top")))
1936         return false;
1937
1938     maintainScrollPositionAtAnchor(anchorElement ? static_cast<Node*>(anchorElement) : frame().document());
1939
1940     // If the anchor accepts keyboard focus, move focus there to aid users relying on keyboard navigation.
1941     if (anchorElement && anchorElement->isFocusable())
1942         frame().document()->setFocusedElement(anchorElement);
1943
1944     return true;
1945 }
1946
1947 void FrameView::maintainScrollPositionAtAnchor(Node* anchorNode)
1948 {
1949     m_maintainScrollPositionAnchor = anchorNode;
1950     if (!m_maintainScrollPositionAnchor)
1951         return;
1952
1953     // We need to update the layout before scrolling, otherwise we could
1954     // really mess things up if an anchor scroll comes at a bad moment.
1955     frame().document()->updateStyleIfNeeded();
1956     // Only do a layout if changes have occurred that make it necessary.
1957     RenderView* renderView = this->renderView();
1958     if (renderView && renderView->needsLayout())
1959         layout();
1960     else
1961         scrollToAnchor();
1962 }
1963
1964 void FrameView::scrollElementToRect(Element* element, const IntRect& rect)
1965 {
1966     frame().document()->updateLayoutIgnorePendingStylesheets();
1967
1968     LayoutRect bounds = element->boundingBox();
1969     int centeringOffsetX = (rect.width() - bounds.width()) / 2;
1970     int centeringOffsetY = (rect.height() - bounds.height()) / 2;
1971     setScrollPosition(IntPoint(bounds.x() - centeringOffsetX - rect.x(), bounds.y() - centeringOffsetY - rect.y()));
1972 }
1973
1974 void FrameView::setScrollPosition(const IntPoint& scrollPoint)
1975 {
1976     TemporaryChange<bool> changeInProgrammaticScroll(m_inProgrammaticScroll, true);
1977     m_maintainScrollPositionAnchor = 0;
1978     ScrollView::setScrollPosition(scrollPoint);
1979 }
1980
1981 void FrameView::delegatesScrollingDidChange()
1982 {
1983     // When we switch to delgatesScrolling mode, we should destroy the scrolling/clipping layers in RenderLayerCompositor.
1984     if (hasCompositedContent())
1985         clearBackingStores();
1986 }
1987
1988 #if USE(TILED_BACKING_STORE)
1989 void FrameView::setFixedVisibleContentRect(const IntRect& visibleContentRect)
1990 {
1991     bool visibleContentSizeDidChange = false;
1992     if (visibleContentRect.size() != this->fixedVisibleContentRect().size()) {
1993         // When the viewport size changes or the content is scaled, we need to
1994         // reposition the fixed and sticky positioned elements.
1995         setViewportConstrainedObjectsNeedLayout();
1996         visibleContentSizeDidChange = true;
1997     }
1998
1999     IntSize offset = scrollOffset();
2000     IntPoint oldPosition = scrollPosition();
2001     ScrollView::setFixedVisibleContentRect(visibleContentRect);
2002     if (offset != scrollOffset()) {
2003         updateLayerPositionsAfterScrolling();
2004         if (frame().page()->settings().acceleratedCompositingForFixedPositionEnabled())
2005             updateCompositingLayersAfterScrolling();
2006         IntPoint newPosition = scrollPosition();
2007         scrollAnimator()->setCurrentPosition(scrollPosition());
2008         scrollPositionChanged(oldPosition, newPosition);
2009     }
2010     if (visibleContentSizeDidChange) {
2011         // Update the scroll-bars to calculate new page-step size.
2012         updateScrollbars(scrollOffset());
2013     }
2014     frame().loader().client().didChangeScrollOffset();
2015 }
2016 #endif
2017
2018 void FrameView::setViewportConstrainedObjectsNeedLayout()
2019 {
2020     if (!hasViewportConstrainedObjects())
2021         return;
2022
2023     for (auto& renderer : *m_viewportConstrainedObjects)
2024         renderer->setNeedsLayout();
2025 }
2026
2027 void FrameView::scrollPositionChangedViaPlatformWidget(const IntPoint& oldPosition, const IntPoint& newPosition)
2028 {
2029     updateLayerPositionsAfterScrolling();
2030     updateCompositingLayersAfterScrolling();
2031     repaintSlowRepaintObjects();
2032     scrollPositionChanged(oldPosition, newPosition);
2033 }
2034
2035 void FrameView::scrollPositionChanged(const IntPoint& oldPosition, const IntPoint& newPosition)
2036 {
2037     frame().eventHandler().sendScrollEvent();
2038     frame().eventHandler().dispatchFakeMouseMoveEventSoon();
2039
2040     if (Document* document = frame().document())
2041         document->sendWillRevealEdgeEventsIfNeeded(oldPosition, newPosition, visibleContentRect(), contentsSize());
2042
2043     if (RenderView* renderView = this->renderView()) {
2044         renderView->resumePausedImageAnimationsIfNeeded();
2045         if (renderView->usesCompositing())
2046             renderView->compositor().frameViewDidScroll();
2047     }
2048 }
2049
2050 void FrameView::updateLayerPositionsAfterScrolling()
2051 {
2052     // If we're scrolling as a result of updating the view size after layout, we'll update widgets and layer positions soon anyway.
2053     if (m_layoutPhase == InViewSizeAdjust)
2054         return;
2055
2056     if (m_nestedLayoutCount <= 1 && hasViewportConstrainedObjects()) {
2057         if (RenderView* renderView = this->renderView()) {
2058             updateWidgetPositions();
2059             renderView->layer()->updateLayerPositionsAfterDocumentScroll();
2060         }
2061     }
2062 }
2063
2064 bool FrameView::shouldUpdateCompositingLayersAfterScrolling() const
2065 {
2066 #if ENABLE(ASYNC_SCROLLING)
2067     // If the scrolling thread is updating the fixed elements, then the FrameView should not update them as well.
2068
2069     Page* page = frame().page();
2070     if (!page)
2071         return true;
2072
2073     if (&page->mainFrame() != &frame())
2074         return true;
2075
2076     ScrollingCoordinator* scrollingCoordinator = page->scrollingCoordinator();
2077     if (!scrollingCoordinator)
2078         return true;
2079
2080     if (!scrollingCoordinator->supportsFixedPositionLayers())
2081         return true;
2082
2083     if (scrollingCoordinator->shouldUpdateScrollLayerPositionSynchronously())
2084         return true;
2085
2086     if (inProgrammaticScroll())
2087         return true;
2088
2089     return false;
2090 #endif
2091     return true;
2092 }
2093
2094 void FrameView::updateCompositingLayersAfterScrolling()
2095 {
2096     if (!shouldUpdateCompositingLayersAfterScrolling())
2097         return;
2098
2099     if (m_nestedLayoutCount <= 1 && hasViewportConstrainedObjects()) {
2100         if (RenderView* renderView = this->renderView())
2101             renderView->compositor().updateCompositingLayers(CompositingUpdateOnScroll);
2102     }
2103 }
2104
2105 bool FrameView::isRubberBandInProgress() const
2106 {
2107     if (scrollbarsSuppressed())
2108         return false;
2109
2110     // If the scrolling thread updates the scroll position for this FrameView, then we should return
2111     // ScrollingCoordinator::isRubberBandInProgress().
2112     if (Page* page = frame().page()) {
2113         if (ScrollingCoordinator* scrollingCoordinator = page->scrollingCoordinator()) {
2114             if (!scrollingCoordinator->shouldUpdateScrollLayerPositionSynchronously())
2115                 return scrollingCoordinator->isRubberBandInProgress();
2116         }
2117     }
2118
2119     // If the main thread updates the scroll position for this FrameView, we should return
2120     // ScrollAnimator::isRubberBandInProgress().
2121     if (ScrollAnimator* scrollAnimator = existingScrollAnimator())
2122         return scrollAnimator->isRubberBandInProgress();
2123
2124     return false;
2125 }
2126
2127 bool FrameView::requestScrollPositionUpdate(const IntPoint& position)
2128 {
2129 #if ENABLE(ASYNC_SCROLLING)
2130     if (TiledBacking* tiledBacking = this->tiledBacking())
2131         tiledBacking->prepopulateRect(FloatRect(position, visibleContentRect().size()));
2132
2133     if (Page* page = frame().page()) {
2134         if (ScrollingCoordinator* scrollingCoordinator = page->scrollingCoordinator())
2135             return scrollingCoordinator->requestScrollPositionUpdate(this, position);
2136     }
2137 #else
2138     UNUSED_PARAM(position);
2139 #endif
2140
2141     return false;
2142 }
2143
2144 HostWindow* FrameView::hostWindow() const
2145 {
2146     if (Page* page = frame().page())
2147         return &page->chrome();
2148     return 0;
2149 }
2150
2151 void FrameView::addTrackedRepaintRect(const FloatRect& r)
2152 {
2153     if (!m_isTrackingRepaints || r.isEmpty())
2154         return;
2155
2156     FloatRect repaintRect = r;
2157     repaintRect.move(-scrollOffset());
2158     m_trackedRepaintRects.append(repaintRect);
2159 }
2160
2161 void FrameView::repaintContentRectangle(const IntRect& r)
2162 {
2163     ASSERT(!frame().ownerElement());
2164
2165     if (!shouldUpdate())
2166         return;
2167
2168     ScrollView::repaintContentRectangle(r);
2169 }
2170
2171 static unsigned countRenderedCharactersInRenderObjectWithThreshold(const RenderObject& renderer, unsigned countSoFar, unsigned threshold)
2172 {
2173     // FIXME: Consider writing this using RenderObject::nextInPreOrder() instead of using recursion.
2174     if (renderer.isText())
2175         countSoFar += toRenderText(renderer).text()->length();
2176
2177     for (RenderObject* child = renderer.firstChildSlow(); child; child = child->nextSibling()) {
2178         if (countSoFar >= threshold)
2179             break;
2180         countSoFar = countRenderedCharactersInRenderObjectWithThreshold(*child, countSoFar, threshold);
2181     }
2182     return countSoFar;
2183 }
2184
2185 bool FrameView::renderedCharactersExceed(unsigned threshold)
2186 {
2187     if (!m_frame->contentRenderer())
2188         return false;
2189     return countRenderedCharactersInRenderObjectWithThreshold(*m_frame->contentRenderer(), 0, threshold) >= threshold;
2190 }
2191
2192 void FrameView::contentsResized()
2193 {
2194     ScrollView::contentsResized();
2195     setNeedsLayout();
2196 }
2197
2198 void FrameView::fixedLayoutSizeChanged()
2199 {
2200     // Can be triggered before the view is set, see comment in FrameView::visibleContentsResized().
2201     // An ASSERT is triggered when a view schedules a layout before being attached to a frame.
2202     if (!frame().view())
2203         return;
2204     ScrollView::fixedLayoutSizeChanged();
2205 }
2206
2207 bool FrameView::shouldLayoutAfterContentsResized() const
2208 {
2209     return !useFixedLayout() || useCustomFixedPositionLayoutRect();
2210 }
2211
2212 void FrameView::visibleContentsResized()
2213 {
2214     // We check to make sure the view is attached to a frame() as this method can
2215     // be triggered before the view is attached by Frame::createView(...) setting
2216     // various values such as setScrollBarModes(...) for example.  An ASSERT is
2217     // triggered when a view is layout before being attached to a frame().
2218     if (!frame().view())
2219         return;
2220
2221 #if PLATFORM(IOS)
2222     if (RenderView* root = m_frame->contentRenderer()) {
2223         if (useCustomFixedPositionLayoutRect() && hasViewportConstrainedObjects()) {
2224             setViewportConstrainedObjectsNeedLayout();
2225             // We must eagerly enter compositing mode because fixed position elements
2226             // will not have been made compositing via a preceding style change before
2227             // m_useCustomFixedPositionLayoutRect was true.
2228             root->compositor().enableCompositingMode();
2229         }
2230     }
2231 #endif
2232
2233     if (shouldLayoutAfterContentsResized() && needsLayout())
2234         layout();
2235
2236     if (RenderView* renderView = this->renderView()) {
2237         if (renderView->usesCompositing())
2238             renderView->compositor().frameViewDidChangeSize();
2239     }
2240 }
2241
2242 void FrameView::addedOrRemovedScrollbar()
2243 {
2244     if (RenderView* renderView = this->renderView()) {
2245         if (renderView->usesCompositing())
2246             renderView->compositor().frameViewDidAddOrRemoveScrollbars();
2247     }
2248 }
2249
2250 void FrameView::disableLayerFlushThrottlingTemporarilyForInteraction()
2251 {
2252     if (RenderView* view = renderView())
2253         view->compositor().disableLayerFlushThrottlingTemporarilyForInteraction();
2254 }
2255
2256 void FrameView::updateLayerFlushThrottlingInAllFrames()
2257 {
2258     bool isMainLoadProgressing = frame().page()->progress().isMainLoadProgressing();
2259     for (Frame* frame = m_frame.get(); frame; frame = frame->tree().traverseNext(m_frame.get())) {
2260         if (RenderView* renderView = frame->contentRenderer())
2261             renderView->compositor().setLayerFlushThrottlingEnabled(isMainLoadProgressing);
2262     }
2263 }
2264
2265 void FrameView::adjustTiledBackingCoverage()
2266 {
2267     if (!m_speculativeTilingEnabled)
2268         enableSpeculativeTilingIfNeeded();
2269
2270     RenderView* renderView = this->renderView();
2271     if (renderView && renderView->layer()->backing())
2272         renderView->layer()->backing()->adjustTiledBackingCoverage();
2273 #if PLATFORM(IOS)
2274     if (LegacyTileCache* tileCache = legacyTileCache())
2275         tileCache->setSpeculativeTileCreationEnabled(m_speculativeTilingEnabled);
2276 #endif
2277 }
2278
2279 static bool shouldEnableSpeculativeTilingDuringLoading(const FrameView& view)
2280 {
2281     return view.isVisuallyNonEmpty() && !view.frame().page()->progress().isMainLoadProgressing();
2282 }
2283
2284 void FrameView::enableSpeculativeTilingIfNeeded()
2285 {
2286     ASSERT(!m_speculativeTilingEnabled);
2287     if (m_wasScrolledByUser) {
2288         m_speculativeTilingEnabled = true;
2289         return;
2290     }
2291     if (!shouldEnableSpeculativeTilingDuringLoading(*this))
2292         return;
2293     if (m_speculativeTilingEnableTimer.isActive())
2294         return;
2295     // Delay enabling a bit as load completion may trigger further loading from scripts.
2296     static const double speculativeTilingEnableDelay = 0.5;
2297     m_speculativeTilingEnableTimer.startOneShot(speculativeTilingEnableDelay);
2298 }
2299
2300 void FrameView::speculativeTilingEnableTimerFired(Timer<FrameView>&)
2301 {
2302     if (m_speculativeTilingEnabled)
2303         return;
2304     m_speculativeTilingEnabled = shouldEnableSpeculativeTilingDuringLoading(*this);
2305     adjustTiledBackingCoverage();
2306 }
2307
2308 void FrameView::layoutTimerFired(Timer<FrameView>&)
2309 {
2310 #ifdef INSTRUMENT_LAYOUT_SCHEDULING
2311     if (!frame().document()->ownerElement())
2312         printf("Layout timer fired at %lld\n", frame().document()->elapsedTime().count());
2313 #endif
2314     layout();
2315 }
2316
2317 void FrameView::scheduleRelayout()
2318 {
2319     // FIXME: We should assert the page is not in the page cache, but that is causing
2320     // too many false assertions.  See <rdar://problem/7218118>.
2321     ASSERT(frame().view() == this);
2322
2323     if (m_layoutRoot) {
2324         m_layoutRoot->markContainingBlocksForLayout(false);
2325         m_layoutRoot = 0;
2326     }
2327     if (!m_layoutSchedulingEnabled)
2328         return;
2329     if (!needsLayout())
2330         return;
2331     if (!frame().document()->shouldScheduleLayout())
2332         return;
2333     InspectorInstrumentation::didInvalidateLayout(&frame());
2334     // When frame flattening is enabled, the contents of the frame could affect the layout of the parent frames.
2335     // Also invalidate parent frame starting from the owner element of this frame.
2336     if (frame().ownerRenderer() && isInChildFrameWithFrameFlattening())
2337         frame().ownerRenderer()->setNeedsLayout(MarkContainingBlockChain);
2338
2339     std::chrono::milliseconds delay = frame().document()->minimumLayoutDelay();
2340     if (m_layoutTimer.isActive() && m_delayedLayout && !delay.count())
2341         unscheduleRelayout();
2342     if (m_layoutTimer.isActive())
2343         return;
2344
2345     m_delayedLayout = delay.count();
2346
2347 #ifdef INSTRUMENT_LAYOUT_SCHEDULING
2348     if (!frame().document()->ownerElement())
2349         printf("Scheduling layout for %d\n", delay);
2350 #endif
2351
2352     m_layoutTimer.startOneShot(delay);
2353 }
2354
2355 static bool isObjectAncestorContainerOf(RenderObject* ancestor, RenderObject* descendant)
2356 {
2357     for (RenderObject* r = descendant; r; r = r->container()) {
2358         if (r == ancestor)
2359             return true;
2360     }
2361     return false;
2362 }
2363
2364 void FrameView::scheduleRelayoutOfSubtree(RenderElement& newRelayoutRoot)
2365 {
2366     ASSERT(renderView());
2367     RenderView& renderView = *this->renderView();
2368
2369     // Try to catch unnecessary work during render tree teardown.
2370     ASSERT(!renderView.documentBeingDestroyed());
2371     ASSERT(frame().view() == this);
2372
2373     if (renderView.needsLayout()) {
2374         newRelayoutRoot.markContainingBlocksForLayout(false);
2375         return;
2376     }
2377
2378     if (!layoutPending() && m_layoutSchedulingEnabled) {
2379         std::chrono::milliseconds delay = renderView.document().minimumLayoutDelay();
2380         ASSERT(!newRelayoutRoot.container() || !newRelayoutRoot.container()->needsLayout());
2381         m_layoutRoot = &newRelayoutRoot;
2382         InspectorInstrumentation::didInvalidateLayout(&frame());
2383         m_delayedLayout = delay.count();
2384         m_layoutTimer.startOneShot(delay);
2385         return;
2386     }
2387
2388     if (m_layoutRoot == &newRelayoutRoot)
2389         return;
2390
2391     if (!m_layoutRoot) {
2392         // Just relayout the subtree.
2393         newRelayoutRoot.markContainingBlocksForLayout(false);
2394         InspectorInstrumentation::didInvalidateLayout(&frame());
2395         return;
2396     }
2397
2398     if (isObjectAncestorContainerOf(m_layoutRoot, &newRelayoutRoot)) {
2399         // Keep the current root.
2400         newRelayoutRoot.markContainingBlocksForLayout(false, m_layoutRoot);
2401         ASSERT(!m_layoutRoot->container() || !m_layoutRoot->container()->needsLayout());
2402         return;
2403     }
2404
2405     if (isObjectAncestorContainerOf(&newRelayoutRoot, m_layoutRoot)) {
2406         // Re-root at newRelayoutRoot.
2407         m_layoutRoot->markContainingBlocksForLayout(false, &newRelayoutRoot);
2408         m_layoutRoot = &newRelayoutRoot;
2409         ASSERT(!m_layoutRoot->container() || !m_layoutRoot->container()->needsLayout());
2410         InspectorInstrumentation::didInvalidateLayout(&frame());
2411         return;
2412     }
2413
2414     // Just do a full relayout.
2415     m_layoutRoot->markContainingBlocksForLayout(false);
2416     m_layoutRoot = 0;
2417     newRelayoutRoot.markContainingBlocksForLayout(false);
2418     InspectorInstrumentation::didInvalidateLayout(&frame());
2419 }
2420
2421 bool FrameView::layoutPending() const
2422 {
2423     return m_layoutTimer.isActive();
2424 }
2425
2426 bool FrameView::needsLayout() const
2427 {
2428     // This can return true in cases where the document does not have a body yet.
2429     // Document::shouldScheduleLayout takes care of preventing us from scheduling
2430     // layout in that case.
2431     RenderView* renderView = this->renderView();
2432     return layoutPending()
2433         || (renderView && renderView->needsLayout())
2434         || m_layoutRoot
2435         || (m_deferSetNeedsLayouts && m_setNeedsLayoutWasDeferred);
2436 }
2437
2438 void FrameView::setNeedsLayout()
2439 {
2440     if (m_deferSetNeedsLayouts) {
2441         m_setNeedsLayoutWasDeferred = true;
2442         return;
2443     }
2444
2445     if (RenderView* renderView = this->renderView())
2446         renderView->setNeedsLayout();
2447 }
2448
2449 void FrameView::unscheduleRelayout()
2450 {
2451     if (!m_layoutTimer.isActive())
2452         return;
2453
2454 #ifdef INSTRUMENT_LAYOUT_SCHEDULING
2455     if (!frame().document()->ownerElement())
2456         printf("Layout timer unscheduled at %d\n", frame().document()->elapsedTime());
2457 #endif
2458
2459     m_layoutTimer.stop();
2460     m_delayedLayout = false;
2461 }
2462
2463 #if ENABLE(REQUEST_ANIMATION_FRAME)
2464 void FrameView::serviceScriptedAnimations(double monotonicAnimationStartTime)
2465 {
2466     for (Frame* frame = m_frame.get(); frame; frame = frame->tree().traverseNext()) {
2467         frame->view()->serviceScrollAnimations();
2468         frame->animation().serviceAnimations();
2469     }
2470
2471     Vector<RefPtr<Document>> documents;
2472     for (Frame* frame = m_frame.get(); frame; frame = frame->tree().traverseNext())
2473         documents.append(frame->document());
2474
2475     for (size_t i = 0; i < documents.size(); ++i)
2476         documents[i]->serviceScriptedAnimations(monotonicAnimationStartTime);
2477 }
2478 #endif
2479
2480 bool FrameView::isTransparent() const
2481 {
2482     return m_isTransparent;
2483 }
2484
2485 void FrameView::setTransparent(bool isTransparent)
2486 {
2487     m_isTransparent = isTransparent;
2488 }
2489
2490 bool FrameView::hasOpaqueBackground() const
2491 {
2492     return !m_isTransparent && !m_baseBackgroundColor.hasAlpha();
2493 }
2494
2495 Color FrameView::baseBackgroundColor() const
2496 {
2497     return m_baseBackgroundColor;
2498 }
2499
2500 void FrameView::setBaseBackgroundColor(const Color& backgroundColor)
2501 {
2502     if (!backgroundColor.isValid())
2503         m_baseBackgroundColor = Color::white;
2504     else
2505         m_baseBackgroundColor = backgroundColor;
2506
2507     recalculateScrollbarOverlayStyle();
2508 }
2509
2510 void FrameView::updateBackgroundRecursively(const Color& backgroundColor, bool transparent)
2511 {
2512     for (Frame* frame = m_frame.get(); frame; frame = frame->tree().traverseNext(m_frame.get())) {
2513         if (FrameView* view = frame->view()) {
2514             view->setTransparent(transparent);
2515             view->setBaseBackgroundColor(backgroundColor);
2516         }
2517     }
2518 }
2519
2520 bool FrameView::hasExtendedBackgroundRectForPainting() const
2521 {
2522     if (!frame().settings().backgroundShouldExtendBeyondPage())
2523         return false;
2524
2525     TiledBacking* tiledBacking = this->tiledBacking();
2526     if (!tiledBacking)
2527         return false;
2528
2529     return tiledBacking->hasMargins();
2530 }
2531
2532 void FrameView::updateExtendBackgroundIfNecessary()
2533 {
2534     ExtendedBackgroundMode mode = calculateExtendedBackgroundMode();
2535     if (mode == ExtendedBackgroundModeNone)
2536         return;
2537
2538     updateTilesForExtendedBackgroundMode(mode);
2539 }
2540
2541 FrameView::ExtendedBackgroundMode FrameView::calculateExtendedBackgroundMode() const
2542 {
2543     // Just because Settings::backgroundShouldExtendBeyondPage() is true does not necessarily mean
2544     // that the background rect needs to be extended for painting. Simple backgrounds can be extended
2545     // just with RenderLayerCompositor::setRootExtendedBackgroundColor(). More complicated backgrounds,
2546     // such as images, require extending the background rect to continue painting into the extended
2547     // region. This function finds out if it is necessary to extend the background rect for painting.
2548
2549 #if PLATFORM(IOS)
2550     // <rdar://problem/16201373>
2551     return ExtendedBackgroundModeNone;
2552 #endif
2553
2554     if (!frame().settings().backgroundShouldExtendBeyondPage())
2555         return ExtendedBackgroundModeNone;
2556
2557     if (!frame().isMainFrame())
2558         return ExtendedBackgroundModeNone;
2559
2560     Document* document = frame().document();
2561     if (!document)
2562         return ExtendedBackgroundModeNone;
2563
2564     auto documentElement = document->documentElement();
2565     auto documentElementRenderer = documentElement ? documentElement->renderer() : nullptr;
2566     if (!documentElementRenderer)
2567         return ExtendedBackgroundModeNone;
2568
2569     auto& renderer = documentElementRenderer->rendererForRootBackground();
2570     if (!renderer.style().hasBackgroundImage())
2571         return ExtendedBackgroundModeNone;
2572
2573     ExtendedBackgroundMode mode = ExtendedBackgroundModeNone;
2574
2575     if (renderer.style().backgroundRepeatX() == RepeatFill)
2576         mode |= ExtendedBackgroundModeHorizontal;
2577     if (renderer.style().backgroundRepeatY() == RepeatFill)
2578         mode |= ExtendedBackgroundModeVertical;
2579
2580     return mode;
2581 }
2582
2583 void FrameView::updateTilesForExtendedBackgroundMode(ExtendedBackgroundMode mode)
2584 {
2585     if (!frame().settings().backgroundShouldExtendBeyondPage())
2586         return;
2587
2588     RenderView* renderView = this->renderView();
2589     if (!renderView)
2590         return;
2591
2592     RenderLayerBacking* backing = renderView->layer()->backing();
2593     if (!backing)
2594         return;
2595
2596     TiledBacking* tiledBacking = backing->graphicsLayer()->tiledBacking();
2597     if (!tiledBacking)
2598         return;
2599
2600     ExtendedBackgroundMode existingMode = ExtendedBackgroundModeNone;
2601     if (tiledBacking->hasVerticalMargins())
2602         existingMode |= ExtendedBackgroundModeVertical;
2603     if (tiledBacking->hasHorizontalMargins())
2604         existingMode |= ExtendedBackgroundModeHorizontal;
2605
2606     if (existingMode == mode)
2607         return;
2608
2609     renderView->compositor().setRootExtendedBackgroundColor(mode == ExtendedBackgroundModeAll ? Color() : documentBackgroundColor());
2610     backing->setTiledBackingHasMargins(mode & ExtendedBackgroundModeHorizontal, mode & ExtendedBackgroundModeVertical);
2611 }
2612
2613 IntRect FrameView::extendedBackgroundRectForPainting() const
2614 {
2615     TiledBacking* tiledBacking = this->tiledBacking();
2616     if (!tiledBacking)
2617         return IntRect();
2618
2619     RenderView* renderView = this->renderView();
2620     if (!renderView)
2621         return IntRect();
2622
2623     LayoutRect extendedRect = renderView->unextendedBackgroundRect(renderView);
2624     if (!tiledBacking->hasMargins())
2625         return pixelSnappedIntRect(extendedRect);
2626
2627     extendedRect.moveBy(LayoutPoint(-tiledBacking->leftMarginWidth(), -tiledBacking->topMarginHeight()));
2628     extendedRect.expand(LayoutSize(tiledBacking->leftMarginWidth() + tiledBacking->rightMarginWidth(), tiledBacking->topMarginHeight() + tiledBacking->bottomMarginHeight()));
2629     return pixelSnappedIntRect(extendedRect);
2630 }
2631
2632 bool FrameView::shouldUpdateWhileOffscreen() const
2633 {
2634     return m_shouldUpdateWhileOffscreen;
2635 }
2636
2637 void FrameView::setShouldUpdateWhileOffscreen(bool shouldUpdateWhileOffscreen)
2638 {
2639     m_shouldUpdateWhileOffscreen = shouldUpdateWhileOffscreen;
2640 }
2641
2642 bool FrameView::shouldUpdate() const
2643 {
2644     if (isOffscreen() && !shouldUpdateWhileOffscreen())
2645         return false;
2646     return true;
2647 }
2648
2649 void FrameView::scrollToAnchor()
2650 {
2651     RefPtr<Node> anchorNode = m_maintainScrollPositionAnchor;
2652     if (!anchorNode)
2653         return;
2654
2655     if (!anchorNode->renderer())
2656         return;
2657
2658     LayoutRect rect;
2659     if (anchorNode != frame().document())
2660         rect = anchorNode->boundingBox();
2661
2662     // Scroll nested layers and frames to reveal the anchor.
2663     // Align to the top and to the closest side (this matches other browsers).
2664     anchorNode->renderer()->scrollRectToVisible(rect, ScrollAlignment::alignToEdgeIfNeeded, ScrollAlignment::alignTopAlways);
2665
2666     if (AXObjectCache* cache = frame().document()->existingAXObjectCache())
2667         cache->handleScrolledToAnchor(anchorNode.get());
2668
2669     // scrollRectToVisible can call into setScrollPosition(), which resets m_maintainScrollPositionAnchor.
2670     m_maintainScrollPositionAnchor = anchorNode;
2671 }
2672
2673 void FrameView::updateEmbeddedObject(RenderEmbeddedObject& embeddedObject)
2674 {
2675     // No need to update if it's already crashed or known to be missing.
2676     if (embeddedObject.isPluginUnavailable())
2677         return;
2678
2679     HTMLFrameOwnerElement& element = embeddedObject.frameOwnerElement();
2680
2681     if (embeddedObject.isSnapshottedPlugIn()) {
2682         if (isHTMLObjectElement(element) || isHTMLEmbedElement(element)) {
2683             HTMLPlugInImageElement& pluginElement = toHTMLPlugInImageElement(element);
2684             pluginElement.checkSnapshotStatus();
2685         }
2686         return;
2687     }
2688
2689     auto weakRenderer = embeddedObject.createWeakPtr();
2690
2691     // FIXME: This could turn into a real virtual dispatch if we defined
2692     // updateWidget(PluginCreationOption) on HTMLElement.
2693     if (isHTMLObjectElement(element) || isHTMLEmbedElement(element) || isHTMLAppletElement(element)) {
2694         HTMLPlugInImageElement& pluginElement = toHTMLPlugInImageElement(element);
2695         if (pluginElement.needsCheckForSizeChange()) {
2696             pluginElement.checkSnapshotStatus();
2697             return;
2698         }
2699         if (pluginElement.needsWidgetUpdate())
2700             pluginElement.updateWidget(CreateAnyWidgetType);
2701     } else
2702         ASSERT_NOT_REACHED();
2703
2704     // It's possible the renderer was destroyed below updateWidget() since loading a plugin may execute arbitrary JavaScript.
2705     if (!weakRenderer)
2706         return;
2707
2708     embeddedObject.updateWidgetPosition();
2709 }
2710
2711 bool FrameView::updateEmbeddedObjects()
2712 {
2713     if (m_nestedLayoutCount > 1 || !m_embeddedObjectsToUpdate || m_embeddedObjectsToUpdate->isEmpty())
2714         return true;
2715
2716     WidgetHierarchyUpdatesSuspensionScope suspendWidgetHierarchyUpdates;
2717
2718     // Insert a marker for where we should stop.
2719     ASSERT(!m_embeddedObjectsToUpdate->contains(nullptr));
2720     m_embeddedObjectsToUpdate->add(nullptr);
2721
2722     while (!m_embeddedObjectsToUpdate->isEmpty()) {
2723         RenderEmbeddedObject* embeddedObject = m_embeddedObjectsToUpdate->takeFirst();
2724         if (!embeddedObject)
2725             break;
2726         updateEmbeddedObject(*embeddedObject);
2727     }
2728
2729     return m_embeddedObjectsToUpdate->isEmpty();
2730 }
2731
2732 void FrameView::updateEmbeddedObjectsTimerFired(Timer<FrameView>*)
2733 {
2734     RefPtr<FrameView> protect(this);
2735     m_updateEmbeddedObjectsTimer.stop();
2736     for (unsigned i = 0; i < maxUpdateEmbeddedObjectsIterations; i++) {
2737         if (updateEmbeddedObjects())
2738             break;
2739     }
2740 }
2741
2742 void FrameView::flushAnyPendingPostLayoutTasks()
2743 {
2744     if (m_postLayoutTasksTimer.isActive())
2745         performPostLayoutTasks();
2746     if (m_updateEmbeddedObjectsTimer.isActive())
2747         updateEmbeddedObjectsTimerFired(nullptr);
2748 }
2749
2750 void FrameView::performPostLayoutTasks()
2751 {
2752     // FIXME: We should not run any JavaScript code in this function.
2753
2754     m_postLayoutTasksTimer.stop();
2755
2756     frame().selection().layoutDidChange();
2757
2758     if (m_nestedLayoutCount <= 1 && frame().document()->documentElement())
2759         fireLayoutRelatedMilestonesIfNeeded();
2760
2761 #if PLATFORM(IOS)
2762     // Only send layout-related delegate callbacks synchronously for the main frame to
2763     // avoid re-entering layout for the main frame while delivering a layout-related delegate
2764     // callback for a subframe.
2765     if (frame().isMainFrame())
2766         frame().page()->chrome().client().didLayout();
2767 #endif
2768
2769 #if ENABLE(FONT_LOAD_EVENTS)
2770     if (RuntimeEnabledFeatures::sharedFeatures().fontLoadEventsEnabled())
2771         frame().document()->fontloader()->didLayout();
2772 #endif
2773
2774     // FIXME: We should consider adding DidLayout as a LayoutMilestone. That would let us merge this
2775     // with didLayout(LayoutMilestones).
2776     frame().loader().client().dispatchDidLayout();
2777
2778     updateWidgetPositions();
2779
2780     // layout() protects FrameView, but it still can get destroyed when updateEmbeddedObjects()
2781     // is called through the post layout timer.
2782     Ref<FrameView> protect(*this);
2783
2784     m_updateEmbeddedObjectsTimer.startOneShot(0);
2785
2786     if (auto* page = frame().page()) {
2787         if (auto* scrollingCoordinator = page->scrollingCoordinator())
2788             scrollingCoordinator->frameViewLayoutUpdated(this);
2789     }
2790
2791     if (RenderView* renderView = this->renderView()) {
2792         if (renderView->usesCompositing())
2793             renderView->compositor().frameViewDidLayout();
2794     }
2795
2796     scrollToAnchor();
2797
2798     sendResizeEventIfNeeded();
2799 }
2800
2801 IntSize FrameView::sizeForResizeEvent() const
2802 {
2803 #if PLATFORM(IOS)
2804     if (m_useCustomSizeForResizeEvent)
2805         return m_customSizeForResizeEvent;
2806 #endif
2807     if (useFixedLayout() && !fixedLayoutSize().isEmpty() && delegatesScrolling())
2808         return fixedLayoutSize();
2809     return visibleContentRectIncludingScrollbars().size();
2810 }
2811
2812 void FrameView::sendResizeEventIfNeeded()
2813 {
2814     if (isInLayout() || needsLayout())
2815         return;
2816
2817     RenderView* renderView = this->renderView();
2818     if (!renderView || renderView->printing())
2819         return;
2820
2821     if (frame().page() && frame().page()->chrome().client().isSVGImageChromeClient())
2822         return;
2823
2824     IntSize currentSize = sizeForResizeEvent();
2825     float currentZoomFactor = renderView->style().zoom();
2826
2827     if (currentSize == m_lastViewportSize && currentZoomFactor == m_lastZoomFactor)
2828         return;
2829
2830     m_lastViewportSize = currentSize;
2831     m_lastZoomFactor = currentZoomFactor;
2832
2833     if (m_firstLayout)
2834         return;
2835
2836 #if PLATFORM(IOS)
2837     // Don't send the resize event if the document is loading. Some pages automatically reload
2838     // when the window is resized; Safari on iOS often resizes the window while setting up its
2839     // viewport. This obviously can cause problems.
2840     if (DocumentLoader* documentLoader = frame().loader().documentLoader()) {
2841         if (documentLoader->isLoadingInAPISense())
2842             return;
2843     }
2844 #endif
2845
2846     bool isMainFrame = frame().isMainFrame();
2847     bool canSendResizeEventSynchronously = isMainFrame && !m_shouldAutoSize;
2848
2849     RefPtr<Event> resizeEvent = Event::create(eventNames().resizeEvent, false, false);
2850     if (canSendResizeEventSynchronously)
2851         frame().document()->dispatchWindowEvent(resizeEvent.release());
2852     else {
2853         // FIXME: Queueing this event for an unpredictable time in the future seems
2854         // intrinsically racy. By the time this resize event fires, the frame might
2855         // be resized again, so we could end up with two resize events for the same size.
2856         frame().document()->enqueueWindowEvent(resizeEvent.release());
2857     }
2858
2859 #if ENABLE(INSPECTOR)
2860     if (InspectorInstrumentation::hasFrontends() && isMainFrame) {
2861         if (Page* page = frame().page()) {
2862             if (InspectorClient* inspectorClient = page->inspectorController().inspectorClient())
2863                 inspectorClient->didResizeMainFrame(&frame());
2864         }
2865     }
2866 #endif
2867 }
2868
2869 void FrameView::willStartLiveResize()
2870 {
2871     ScrollView::willStartLiveResize();
2872     adjustTiledBackingCoverage();
2873 }
2874
2875 void FrameView::willEndLiveResize()
2876 {
2877     ScrollView::willEndLiveResize();
2878     adjustTiledBackingCoverage();
2879 }
2880
2881 void FrameView::postLayoutTimerFired(Timer<FrameView>&)
2882 {
2883     performPostLayoutTasks();
2884 }
2885
2886 void FrameView::autoSizeIfEnabled()
2887 {
2888     if (!m_shouldAutoSize)
2889         return;
2890
2891     if (m_inAutoSize)
2892         return;
2893
2894     TemporaryChange<bool> changeInAutoSize(m_inAutoSize, true);
2895
2896     Document* document = frame().document();
2897     if (!document)
2898         return;
2899
2900     RenderView* documentView = document->renderView();
2901     Element* documentElement = document->documentElement();
2902     if (!documentView || !documentElement)
2903         return;
2904
2905     // Start from the minimum size and allow it to grow.
2906     resize(m_minAutoSize.width(), m_minAutoSize.height());
2907
2908     IntSize size = frameRect().size();
2909
2910     // Do the resizing twice. The first time is basically a rough calculation using the preferred width
2911     // which may result in a height change during the second iteration.
2912     for (int i = 0; i < 2; i++) {
2913         // Update various sizes including contentsSize, scrollHeight, etc.
2914         document->updateLayoutIgnorePendingStylesheets();
2915         int width = documentView->minPreferredLogicalWidth();
2916         int height = documentView->documentRect().height();
2917         IntSize newSize(width, height);
2918
2919         // Check to see if a scrollbar is needed for a given dimension and
2920         // if so, increase the other dimension to account for the scrollbar.
2921         // Since the dimensions are only for the view rectangle, once a
2922         // dimension exceeds the maximum, there is no need to increase it further.
2923         if (newSize.width() > m_maxAutoSize.width()) {
2924             RefPtr<Scrollbar> localHorizontalScrollbar = horizontalScrollbar();
2925             if (!localHorizontalScrollbar)
2926                 localHorizontalScrollbar = createScrollbar(HorizontalScrollbar);
2927             if (!localHorizontalScrollbar->isOverlayScrollbar())
2928                 newSize.setHeight(newSize.height() + localHorizontalScrollbar->height());
2929
2930             // Don't bother checking for a vertical scrollbar because the width is at
2931             // already greater the maximum.
2932         } else if (newSize.height() > m_maxAutoSize.height()) {
2933             RefPtr<Scrollbar> localVerticalScrollbar = verticalScrollbar();
2934             if (!localVerticalScrollbar)
2935                 localVerticalScrollbar = createScrollbar(VerticalScrollbar);
2936             if (!localVerticalScrollbar->isOverlayScrollbar())
2937                 newSize.setWidth(newSize.width() + localVerticalScrollbar->width());
2938
2939             // Don't bother checking for a horizontal scrollbar because the height is
2940             // already greater the maximum.
2941         }
2942
2943         // Ensure the size is at least the min bounds.
2944         newSize = newSize.expandedTo(m_minAutoSize);
2945
2946         // Bound the dimensions by the max bounds and determine what scrollbars to show.
2947         ScrollbarMode horizonalScrollbarMode = ScrollbarAlwaysOff;
2948         if (newSize.width() > m_maxAutoSize.width()) {
2949             newSize.setWidth(m_maxAutoSize.width());
2950             horizonalScrollbarMode = ScrollbarAlwaysOn;
2951         }
2952         ScrollbarMode verticalScrollbarMode = ScrollbarAlwaysOff;
2953         if (newSize.height() > m_maxAutoSize.height()) {
2954             newSize.setHeight(m_maxAutoSize.height());
2955             verticalScrollbarMode = ScrollbarAlwaysOn;
2956         }
2957
2958         if (newSize == size)
2959             continue;
2960
2961         // While loading only allow the size to increase (to avoid twitching during intermediate smaller states)
2962         // unless autoresize has just been turned on or the maximum size is smaller than the current size.
2963         if (m_didRunAutosize && size.height() <= m_maxAutoSize.height() && size.width() <= m_maxAutoSize.width()
2964             && !frame().loader().isComplete() && (newSize.height() < size.height() || newSize.width() < size.width()))
2965             break;
2966
2967         resize(newSize.width(), newSize.height());
2968         // Force the scrollbar state to avoid the scrollbar code adding them and causing them to be needed. For example,
2969         // a vertical scrollbar may cause text to wrap and thus increase the height (which is the only reason the scollbar is needed).
2970         setVerticalScrollbarLock(false);
2971         setHorizontalScrollbarLock(false);
2972         setScrollbarModes(horizonalScrollbarMode, verticalScrollbarMode, true, true);
2973     }
2974
2975     m_autoSizeContentSize = contentsSize();
2976
2977     if (m_autoSizeFixedMinimumHeight) {
2978         resize(m_autoSizeContentSize.width(), std::max(m_autoSizeFixedMinimumHeight, m_autoSizeContentSize.height()));
2979         document->updateLayoutIgnorePendingStylesheets();
2980     }
2981
2982     m_didRunAutosize = true;
2983 }
2984
2985 void FrameView::setAutoSizeFixedMinimumHeight(int fixedMinimumHeight)
2986 {
2987     if (m_autoSizeFixedMinimumHeight == fixedMinimumHeight)
2988         return;
2989
2990     m_autoSizeFixedMinimumHeight = fixedMinimumHeight;
2991
2992     setNeedsLayout();
2993 }
2994
2995 void FrameView::updateOverflowStatus(bool horizontalOverflow, bool verticalOverflow)
2996 {
2997     if (!m_viewportRenderer)
2998         return;
2999
3000     if (m_overflowStatusDirty) {
3001         m_horizontalOverflow = horizontalOverflow;
3002         m_verticalOverflow = verticalOverflow;
3003         m_overflowStatusDirty = false;
3004         return;
3005     }
3006
3007     bool horizontalOverflowChanged = (m_horizontalOverflow != horizontalOverflow);
3008     bool verticalOverflowChanged = (m_verticalOverflow != verticalOverflow);
3009
3010     if (horizontalOverflowChanged || verticalOverflowChanged) {
3011         m_horizontalOverflow = horizontalOverflow;
3012         m_verticalOverflow = verticalOverflow;
3013
3014         RefPtr<OverflowEvent> overflowEvent = OverflowEvent::create(horizontalOverflowChanged, horizontalOverflow,
3015             verticalOverflowChanged, verticalOverflow);
3016         overflowEvent->setTarget(m_viewportRenderer->element());
3017
3018         frame().document()->enqueueOverflowEvent(overflowEvent.release());
3019     }
3020
3021 }
3022
3023 const Pagination& FrameView::pagination() const
3024 {
3025     if (m_pagination != Pagination())
3026         return m_pagination;
3027
3028     if (frame().isMainFrame())
3029         return frame().page()->pagination();
3030
3031     return m_pagination;
3032 }
3033
3034 void FrameView::setPagination(const Pagination& pagination)
3035 {
3036     if (m_pagination == pagination)
3037         return;
3038
3039     m_pagination = pagination;
3040
3041     frame().document()->styleResolverChanged(DeferRecalcStyle);
3042 }
3043
3044 IntRect FrameView::windowClipRect(bool clipToContents) const
3045 {
3046     ASSERT(frame().view() == this);
3047
3048     if (paintsEntireContents())
3049         return IntRect(IntPoint(), totalContentsSize());
3050
3051     // Set our clip rect to be our contents.
3052     IntRect clipRect;
3053     if (clipToContents)
3054         clipRect = contentsToWindow(visibleContentRect(LegacyIOSDocumentVisibleRect));
3055     else
3056         clipRect = contentsToWindow(visibleContentRectIncludingScrollbars(LegacyIOSDocumentVisibleRect));
3057     if (!frame().ownerElement())
3058         return clipRect;
3059
3060     // Take our owner element and get its clip rect.
3061     HTMLFrameOwnerElement* ownerElement = frame().ownerElement();
3062     if (FrameView* parentView = ownerElement->document().view())
3063         clipRect.intersect(parentView->windowClipRectForFrameOwner(ownerElement, true));
3064     return clipRect;
3065 }
3066
3067 IntRect FrameView::windowClipRectForFrameOwner(const HTMLFrameOwnerElement* ownerElement, bool clipToLayerContents) const
3068 {
3069     // The renderer can sometimes be null when style="display:none" interacts
3070     // with external content and plugins.
3071     if (!ownerElement->renderer())
3072         return windowClipRect();
3073
3074     // If we have no layer, just return our window clip rect.
3075     const RenderLayer* enclosingLayer = ownerElement->renderer()->enclosingLayer();
3076     if (!enclosingLayer)
3077         return windowClipRect();
3078
3079     // Apply the clip from the layer.
3080     IntRect clipRect;
3081     if (clipToLayerContents)
3082         clipRect = pixelSnappedIntRect(enclosingLayer->childrenClipRect());
3083     else
3084         clipRect = pixelSnappedIntRect(enclosingLayer->selfClipRect());
3085     clipRect = contentsToWindow(clipRect);
3086     return intersection(clipRect, windowClipRect());
3087 }
3088
3089 bool FrameView::isActive() const
3090 {
3091     Page* page = frame().page();
3092     return page && page->focusController().isActive();
3093 }
3094
3095 bool FrameView::updatesScrollLayerPositionOnMainThread() const
3096 {
3097     if (Page* page = frame().page()) {
3098         if (ScrollingCoordinator* scrollingCoordinator = page->scrollingCoordinator())
3099             return scrollingCoordinator->shouldUpdateScrollLayerPositionSynchronously();
3100     }
3101
3102     return true;
3103 }
3104
3105 void FrameView::scrollTo(const IntSize& newOffset)
3106 {
3107     LayoutSize offset = scrollOffset();
3108     IntPoint oldPosition = scrollPosition();
3109     ScrollView::scrollTo(newOffset);
3110     if (offset != scrollOffset())
3111         scrollPositionChanged(oldPosition, scrollPosition());
3112     frame().loader().client().didChangeScrollOffset();
3113 }
3114
3115 void FrameView::invalidateScrollbarRect(Scrollbar* scrollbar, const IntRect& rect)
3116 {
3117     // Add in our offset within the FrameView.
3118     IntRect dirtyRect = rect;
3119     dirtyRect.moveBy(scrollbar->location());
3120     invalidateRect(dirtyRect);
3121 }
3122
3123 IntRect FrameView::windowResizerRect() const
3124 {
3125     if (Page* page = frame().page())
3126         return page->chrome().windowResizerRect();
3127     return IntRect();
3128 }
3129
3130 float FrameView::visibleContentScaleFactor() const
3131 {
3132     if (!frame().isMainFrame() || !frame().settings().delegatesPageScaling())
3133         return 1;
3134
3135     return frame().page()->pageScaleFactor();
3136 }
3137
3138 void FrameView::setVisibleScrollerThumbRect(const IntRect& scrollerThumb)
3139 {
3140     if (!frame().isMainFrame())
3141         return;
3142
3143     frame().page()->chrome().client().notifyScrollerThumbIsVisibleInRect(scrollerThumb);
3144 }
3145
3146 ScrollableArea* FrameView::enclosingScrollableArea() const
3147 {
3148     // FIXME: Walk up the frame tree and look for a scrollable parent frame or RenderLayer.
3149     return 0;
3150 }
3151
3152 IntRect FrameView::scrollableAreaBoundingBox() const
3153 {
3154     RenderWidget* ownerRenderer = frame().ownerRenderer();
3155     if (!ownerRenderer)
3156         return frameRect();
3157
3158     return ownerRenderer->absoluteContentQuad().enclosingBoundingBox();
3159 }
3160
3161 bool FrameView::isScrollable()
3162 {
3163     // Check for:
3164     // 1) If there an actual overflow.
3165     // 2) display:none or visibility:hidden set to self or inherited.
3166     // 3) overflow{-x,-y}: hidden;
3167     // 4) scrolling: no;
3168
3169     // Covers #1
3170     IntSize totalContentsSize = this->totalContentsSize();
3171     IntSize visibleContentSize = visibleContentRect(LegacyIOSDocumentVisibleRect).size();
3172     if ((totalContentsSize.height() <= visibleContentSize.height() && totalContentsSize.width() <= visibleContentSize.width()))
3173         return false;
3174
3175     // Covers #2.
3176     HTMLFrameOwnerElement* owner = frame().ownerElement();
3177     if (owner && (!owner->renderer() || !owner->renderer()->visibleToHitTesting()))
3178         return false;
3179
3180     // Cover #3 and #4.
3181     ScrollbarMode horizontalMode;
3182     ScrollbarMode verticalMode;
3183     calculateScrollbarModesForLayout(horizontalMode, verticalMode, RulesFromWebContentOnly);
3184     if (horizontalMode == ScrollbarAlwaysOff && verticalMode == ScrollbarAlwaysOff)
3185         return false;
3186
3187     return true;
3188 }
3189
3190 void FrameView::updateScrollableAreaSet()
3191 {
3192     // That ensures that only inner frames are cached.
3193     FrameView* parentFrameView = this->parentFrameView();
3194     if (!parentFrameView)
3195         return;
3196
3197     if (!isScrollable()) {
3198         parentFrameView->removeScrollableArea(this);
3199         return;
3200     }
3201
3202     parentFrameView->addScrollableArea(this);
3203 }
3204
3205 bool FrameView::shouldSuspendScrollAnimations() const
3206 {
3207     return frame().loader().state() != FrameStateComplete;
3208 }
3209
3210 void FrameView::scrollbarStyleChanged(int newStyle, bool forceUpdate)
3211 {
3212     if (!frame().isMainFrame())
3213         return;
3214
3215     frame().page()->chrome().client().recommendedScrollbarStyleDidChange(newStyle);
3216
3217     if (forceUpdate)
3218         ScrollView::scrollbarStyleChanged(newStyle, forceUpdate);
3219 }
3220
3221 void FrameView::notifyPageThatContentAreaWillPaint() const
3222 {
3223     Page* page = frame().page();
3224     if (!page)
3225         return;
3226
3227     contentAreaWillPaint();
3228
3229     if (!m_scrollableAreas)
3230         return;
3231
3232     for (auto& scrollableArea : *m_scrollableAreas)
3233         scrollableArea->contentAreaWillPaint();
3234 }
3235
3236 bool FrameView::scrollAnimatorEnabled() const
3237 {
3238 #if ENABLE(SMOOTH_SCROLLING)
3239     if (Page* page = frame().page())
3240         return page->settings().scrollAnimatorEnabled();
3241 #endif
3242
3243     return false;
3244 }
3245
3246 #if ENABLE(DASHBOARD_SUPPORT)
3247 void FrameView::updateAnnotatedRegions()
3248 {
3249     Document* document = frame().document();
3250     if (!document->hasAnnotatedRegions())
3251         return;
3252     Vector<AnnotatedRegionValue> newRegions;
3253     document->renderBox()->collectAnnotatedRegions(newRegions);
3254     if (newRegions == document->annotatedRegions())
3255         return;
3256     document->setAnnotatedRegions(newRegions);
3257     Page* page = frame().page();
3258     if (!page)
3259         return;
3260     page->chrome().client().annotatedRegionsChanged();
3261 }
3262 #endif
3263
3264 void FrameView::updateScrollCorner()
3265 {
3266     RenderElement* renderer = 0;
3267     RefPtr<RenderStyle> cornerStyle;
3268     IntRect cornerRect = scrollCornerRect();
3269
3270     if (!cornerRect.isEmpty()) {
3271         // Try the <body> element first as a scroll corner source.
3272         Document* doc = frame().document();
3273         Element* body = doc ? doc->body() : 0;
3274         if (body && body->renderer()) {
3275             renderer = body->renderer();
3276             cornerStyle = renderer->getUncachedPseudoStyle(PseudoStyleRequest(SCROLLBAR_CORNER), &renderer->style());
3277         }
3278
3279         if (!cornerStyle) {
3280             // If the <body> didn't have a custom style, then the root element might.
3281             Element* docElement = doc ? doc->documentElement() : 0;
3282             if (docElement && docElement->renderer()) {
3283                 renderer = docElement->renderer();
3284                 cornerStyle = renderer->getUncachedPseudoStyle(PseudoStyleRequest(SCROLLBAR_CORNER), &renderer->style());
3285             }
3286         }
3287
3288         if (!cornerStyle) {
3289             // If we have an owning iframe/frame element, then it can set the custom scrollbar also.
3290             if (RenderWidget* renderer = frame().ownerRenderer())
3291                 cornerStyle = renderer->getUncachedPseudoStyle(PseudoStyleRequest(SCROLLBAR_CORNER), &renderer->style());
3292         }
3293     }
3294
3295     if (!cornerStyle)
3296         m_scrollCorner = nullptr;
3297     else {
3298         if (!m_scrollCorner) {
3299             m_scrollCorner = createRenderer<RenderScrollbarPart>(renderer->document(), cornerStyle.releaseNonNull());
3300             m_scrollCorner->initializeStyle();
3301         } else
3302             m_scrollCorner->setStyle(cornerStyle.releaseNonNull());
3303         invalidateScrollCorner(cornerRect);
3304     }
3305
3306     ScrollView::updateScrollCorner();
3307 }
3308
3309 void FrameView::paintScrollCorner(GraphicsContext* context, const IntRect& cornerRect)
3310 {
3311     if (context->updatingControlTints()) {
3312         updateScrollCorner();
3313         return;
3314     }
3315
3316     if (m_scrollCorner) {
3317         if (frame().isMainFrame())
3318             context->fillRect(cornerRect, baseBackgroundColor(), ColorSpaceDeviceRGB);
3319         m_scrollCorner->paintIntoRect(context, cornerRect.location(), cornerRect);
3320         return;
3321     }
3322
3323     ScrollView::paintScrollCorner(context, cornerRect);
3324 }
3325
3326 void FrameView::paintScrollbar(GraphicsContext* context, Scrollbar* bar, const IntRect& rect)
3327 {
3328     if (bar->isCustomScrollbar() && frame().isMainFrame()) {
3329         IntRect toFill = bar->frameRect();
3330         toFill.intersect(rect);
3331         context->fillRect(toFill, baseBackgroundColor(), ColorSpaceDeviceRGB);
3332     }
3333
3334     ScrollView::paintScrollbar(context, bar, rect);
3335 }
3336
3337 Color FrameView::documentBackgroundColor() const
3338 {
3339     // <https://bugs.webkit.org/show_bug.cgi?id=59540> We blend the background color of
3340     // the document and the body against the base background color of the frame view.
3341     // Background images are unfortunately impractical to include.
3342
3343     // Return invalid Color objects whenever there is insufficient information.
3344     if (!frame().document())
3345         return Color();
3346
3347     Element* htmlElement = frame().document()->documentElement();
3348     Element* bodyElement = frame().document()->body();
3349
3350     // Start with invalid colors.
3351     Color htmlBackgroundColor;
3352     Color bodyBackgroundColor;
3353     if (htmlElement && htmlElement->renderer())
3354         htmlBackgroundColor = htmlElement->renderer()->style().visitedDependentColor(CSSPropertyBackgroundColor);
3355     if (bodyElement && bodyElement->renderer())
3356         bodyBackgroundColor = bodyElement->renderer()->style().visitedDependentColor(CSSPropertyBackgroundColor);
3357
3358     if (!bodyBackgroundColor.isValid()) {
3359         if (!htmlBackgroundColor.isValid())
3360             return Color();
3361         return baseBackgroundColor().blend(htmlBackgroundColor);
3362     }
3363
3364     if (!htmlBackgroundColor.isValid())
3365         return baseBackgroundColor().blend(bodyBackgroundColor);
3366
3367     // We take the aggregate of the base background color
3368     // the <html> background color, and the <body>
3369     // background color to find the document color. The
3370     // addition of the base background color is not
3371     // technically part of the document background, but it
3372     // otherwise poses problems when the aggregate is not
3373     // fully opaque.
3374     return baseBackgroundColor().blend(htmlBackgroundColor).blend(bodyBackgroundColor);
3375 }
3376
3377 bool FrameView::hasCustomScrollbars() const
3378 {
3379     for (auto& widget : children()) {
3380         if (widget->isFrameView()) {
3381             if (toFrameView(*widget).hasCustomScrollbars())
3382                 return true;
3383         } else if (widget->isScrollbar()) {
3384             if (toScrollbar(*widget).isCustomScrollbar())
3385                 return true;
3386         }
3387     }
3388
3389     return false;
3390 }
3391
3392 FrameView* FrameView::parentFrameView() const
3393 {
3394     if (!parent())
3395         return 0;
3396
3397     if (Frame* parentFrame = frame().tree().parent())
3398         return parentFrame->view();
3399
3400     return 0;
3401 }
3402
3403 bool FrameView::isInChildFrameWithFrameFlattening() const
3404 {
3405     if (!parent() || !frame().ownerElement())
3406         return false;
3407
3408     // Frame flattening applies when the owner element is either in a frameset or
3409     // an iframe with flattening parameters.
3410     if (frame().ownerElement()->hasTagName(iframeTag)) {
3411         RenderIFrame* iframeRenderer = toRenderIFrame(frame().ownerElement()->renderWidget());
3412         if (iframeRenderer->flattenFrame())
3413             return true;
3414     }
3415
3416     if (!frameFlatteningEnabled())
3417         return false;
3418
3419     if (frame().ownerElement()->hasTagName(frameTag))
3420         return true;
3421
3422     return false;
3423 }
3424
3425 void FrameView::startLayoutAtMainFrameViewIfNeeded(bool allowSubtree)
3426 {
3427     // When we start a layout at the child level as opposed to the topmost frame view and this child
3428     // frame requires flattening, we need to re-initiate the layout at the topmost view. Layout
3429     // will hit this view eventually.
3430     FrameView* parentView = parentFrameView();
3431     if (!parentView)
3432         return;
3433
3434     // In the middle of parent layout, no need to restart from topmost.
3435     if (parentView->m_nestedLayoutCount)
3436         return;
3437
3438     // Parent tree is clean. Starting layout from it would have no effect.
3439     if (!parentView->needsLayout())
3440         return;
3441
3442     while (parentView->parentFrameView())
3443         parentView = parentView->parentFrameView();
3444
3445     parentView->layout(allowSubtree);
3446
3447     RenderElement* root = m_layoutRoot ? m_layoutRoot : frame().document()->renderView();
3448     ASSERT_UNUSED(root, !root->needsLayout());
3449 }
3450
3451 void FrameView::updateControlTints()
3452 {
3453     // This is called when control tints are changed from aqua/graphite to clear and vice versa.
3454     // We do a "fake" paint, and when the theme gets a paint call, it can then do an invalidate.
3455     // This is only done if the theme supports control tinting. It's up to the theme and platform
3456     // to define when controls get the tint and to call this function when that changes.
3457
3458     // Optimize the common case where we bring a window to the front while it's still empty.
3459     if (frame().document()->url().isEmpty())
3460         return;
3461
3462     RenderView* renderView = this->renderView();
3463     if ((renderView && renderView->theme().supportsControlTints()) || hasCustomScrollbars())
3464         paintControlTints();
3465 }
3466
3467 void FrameView::paintControlTints()
3468 {
3469     if (needsLayout())
3470         layout();
3471     PlatformGraphicsContext* const noContext = 0;
3472     GraphicsContext context(noContext);
3473     context.setUpdatingControlTints(true);
3474     if (platformWidget()) {
3475         // FIXME: consult paintsEntireContents().
3476         paintContents(&context, visibleContentRect(LegacyIOSDocumentVisibleRect));
3477     } else
3478         paint(&context, frameRect());
3479 }
3480
3481 bool FrameView::wasScrolledByUser() const
3482 {
3483     return m_wasScrolledByUser;
3484 }
3485
3486 void FrameView::setWasScrolledByUser(bool wasScrolledByUser)
3487 {
3488     if (m_inProgrammaticScroll)
3489         return;
3490     m_maintainScrollPositionAnchor = 0;
3491     if (m_wasScrolledByUser == wasScrolledByUser)
3492         return;
3493     m_wasScrolledByUser = wasScrolledByUser;
3494     adjustTiledBackingCoverage();
3495 }
3496
3497 void FrameView::willPaintContents(GraphicsContext* context, const IntRect& dirtyRect, PaintingState& paintingState)
3498 {
3499     Document* document = frame().document();
3500
3501     if (!context->paintingDisabled())
3502         InspectorInstrumentation::willPaint(renderView());
3503
3504     paintingState.isTopLevelPainter = !sCurrentPaintTimeStamp;
3505
3506     if (paintingState.isTopLevelPainter && memoryPressureHandler().isUnderMemoryPressure()) {
3507         LOG(MemoryPressure, "Under memory pressure: %s", WTF_PRETTY_FUNCTION);
3508
3509         // To avoid unnecessary image decoding, we don't prune recently-decoded live resources here since
3510         // we might need some live bitmaps on painting.
3511         memoryCache()->prune();
3512     }
3513
3514     if (paintingState.isTopLevelPainter)
3515         sCurrentPaintTimeStamp = monotonicallyIncreasingTime();
3516
3517     paintingState.paintBehavior = m_paintBehavior;
3518
3519     if (FrameView* parentView = parentFrameView()) {
3520         if (parentView->paintBehavior() & PaintBehaviorFlattenCompositingLayers)
3521             m_paintBehavior |= PaintBehaviorFlattenCompositingLayers;
3522     }
3523
3524     if (m_paintBehavior == PaintBehaviorNormal)
3525         document->markers().invalidateRenderedRectsForMarkersInRect(dirtyRect);
3526
3527     if (document->printing())
3528         m_paintBehavior |= PaintBehaviorFlattenCompositingLayers;
3529
3530     paintingState.isFlatteningPaintOfRootFrame = (m_paintBehavior & PaintBehaviorFlattenCompositingLayers) && !frame().ownerElement();
3531     if (paintingState.isFlatteningPaintOfRootFrame)
3532         notifyWidgetsInAllFrames(WillPaintFlattened);
3533
3534     ASSERT(!m_isPainting);
3535     m_isPainting = true;
3536 }
3537
3538 void FrameView::didPaintContents(GraphicsContext* context, const IntRect& dirtyRect, PaintingState& paintingState)
3539 {
3540     m_isPainting = false;
3541
3542     if (paintingState.isFlatteningPaintOfRootFrame)
3543         notifyWidgetsInAllFrames(DidPaintFlattened);
3544
3545     m_paintBehavior = paintingState.paintBehavior;
3546     m_lastPaintTime = monotonicallyIncreasingTime();
3547
3548     // Painting can lead to decoding of large amounts of bitmaps
3549     // If we are low on memory, wipe them out after the paint.
3550     if (paintingState.isTopLevelPainter && memoryPressureHandler().isUnderMemoryPressure())
3551         memoryCache()->pruneLiveResources(true);
3552
3553     // Regions may have changed as a result of the visibility/z-index of element changing.
3554 #if ENABLE(DASHBOARD_SUPPORT)
3555     if (frame().document()->annotatedRegionsDirty())
3556         updateAnnotatedRegions();
3557 #endif
3558
3559     if (paintingState.isTopLevelPainter)
3560         sCurrentPaintTimeStamp = 0;
3561
3562     if (!context->paintingDisabled()) {
3563         InspectorInstrumentation::didPaint(renderView(), context, dirtyRect);
3564         // FIXME: should probably not fire milestones for snapshot painting. https://bugs.webkit.org/show_bug.cgi?id=117623
3565         firePaintRelatedMilestonesIfNeeded();
3566     }
3567 }
3568
3569 void FrameView::paintContents(GraphicsContext* context, const IntRect& dirtyRect)
3570 {
3571 #ifndef NDEBUG
3572     bool fillWithRed;
3573     if (frame().document()->printing())
3574         fillWithRed = false; // Printing, don't fill with red (can't remember why).
3575     else if (frame().ownerElement())
3576         fillWithRed = false; // Subframe, don't fill with red.
3577     else if (isTransparent())
3578         fillWithRed = false; // Transparent, don't fill with red.
3579     else if (m_paintBehavior & PaintBehaviorSelectionOnly)
3580         fillWithRed = false; // Selections are transparent, don't fill with red.
3581     else if (m_nodeToDraw)
3582         fillWithRed = false; // Element images are transparent, don't fill with red.
3583     else
3584         fillWithRed = true;
3585
3586     if (fillWithRed)
3587         context->fillRect(dirtyRect, Color(0xFF, 0, 0), ColorSpaceDeviceRGB);
3588 #endif
3589
3590     RenderView* renderView = this->renderView();
3591     if (!renderView) {
3592         LOG_ERROR("called FrameView::paint with nil renderer");
3593         return;
3594     }
3595
3596     ASSERT(!needsLayout());
3597     if (needsLayout())
3598         return;
3599
3600     PaintingState paintingState;
3601     willPaintContents(context, dirtyRect, paintingState);
3602
3603     FontCachePurgePreventer fontCachePurgePreventer;
3604
3605     // m_nodeToDraw is used to draw only one element (and its descendants)
3606     RenderObject* eltRenderer = m_nodeToDraw ? m_nodeToDraw->renderer() : 0;
3607     RenderLayer* rootLayer = renderView->layer();
3608
3609 #ifndef NDEBUG
3610     RenderElement::SetLayoutNeededForbiddenScope forbidSetNeedsLayout(&rootLayer->renderer());
3611 #endif
3612
3613     rootLayer->paint(context, dirtyRect, m_paintBehavior, eltRenderer);
3614     if (rootLayer->containsDirtyOverlayScrollbars())