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