WebCore/platform/chromium/ScrollbarThemeChromiumMac.mm

   1 /*
   2  * Copyright (C) 2008 Apple Inc. All Rights Reserved.
   3  * Copyright (C) 2009 Google Inc. All Rights Reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
  15  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  17  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
  18  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  19  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  20  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  21  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
  22  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  24  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  25  */
  26
  27 #include "config.h"
  28 #include "ScrollbarThemeChromiumMac.h"
  29
  30 // FIXME: Remove this (always use WebThemeEngine) once we rebaseline tests
  31 #define USE_WEB_THEME_ENGINE_TO_PAINT_THUMB 1
  32
  33 #if USE_WEB_THEME_ENGINE_TO_PAINT_THUMB
  34 #include "ChromiumBridge.h"
  35 #include "FrameView.h"
  36 #endif
  37 #include "ImageBuffer.h"
  38 #include "PlatformMouseEvent.h"
  39 #include "ScrollView.h"
  40 #include <Carbon/Carbon.h>
  41 #include <wtf/StdLibExtras.h>
  42 #include <wtf/UnusedParam.h>
  43
  44
  45 // FIXME: There are repainting problems due to Aqua scroll bar buttons' visual overflow.
  46
  47 using namespace std;
  48 using namespace WebCore;
  49
  50 // This file (and its associated .h file) is a clone of ScrollbarThemeMac.mm.
  51 // Because we want to draw tickmarks in the scrollbar, we must maintain a fork.
  52 // Please maintain this file by performing parallel changes to it.
  53 //
  54 // The only changes from ScrollbarThemeMac should be:
  55 // - The classname change from ScrollbarThemeMac to ScrollbarThemeChromiumMac.
  56 // - In paint() the code to paint the track, tickmarks, and thumb separately.
  57 //
  58 // For all other differences, if it was introduced in this file, then the
  59 // maintainer forgot to include it in the list; otherwise it is an update that
  60 // should have been applied to this file but was not.
  61
  62 static HashSet<Scrollbar*>* gScrollbars;
  63
  64 @interface ScrollbarPrefsObserver : NSObject
  65 {
  66
  67 }
  68
  69 + (void)registerAsObserver;
  70 + (void)appearancePrefsChanged:(NSNotification*)theNotification;
  71 + (void)behaviorPrefsChanged:(NSNotification*)theNotification;
  72
  73 @end
  74
  75 @implementation ScrollbarPrefsObserver
  76
  77 + (void)appearancePrefsChanged:(NSNotification*)unusedNotification
  78 {
  79     UNUSED_PARAM(unusedNotification);
  80
  81     static_cast<ScrollbarThemeChromiumMac*>(ScrollbarTheme::nativeTheme())->preferencesChanged();
  82     if (!gScrollbars)
  83         return;
  84     HashSet<Scrollbar*>::iterator end = gScrollbars->end();
  85     for (HashSet<Scrollbar*>::iterator it = gScrollbars->begin(); it != end; ++it) {
  86         (*it)->styleChanged();
  87         (*it)->invalidate();
  88     }
  89 }
  90
  91 + (void)behaviorPrefsChanged:(NSNotification*)unusedNotification
  92 {
  93     UNUSED_PARAM(unusedNotification);
  94
  95     static_cast<ScrollbarThemeChromiumMac*>(ScrollbarTheme::nativeTheme())->preferencesChanged();
  96 }
  97
  98 + (void)registerAsObserver
  99 {
 100     [[NSDistributedNotificationCenter defaultCenter] addObserver:self selector:@selector(appearancePrefsChanged:) name:@"AppleAquaScrollBarVariantChanged" object:nil suspensionBehavior:NSNotificationSuspensionBehaviorDeliverImmediately];
 101     [[NSDistributedNotificationCenter defaultCenter] addObserver:self selector:@selector(behaviorPrefsChanged:) name:@"AppleNoRedisplayAppearancePreferenceChanged" object:nil suspensionBehavior:NSNotificationSuspensionBehaviorCoalesce];
 102 }
 103
 104 @end
 105
 106 namespace WebCore {
 107
 108 ScrollbarTheme* ScrollbarTheme::nativeTheme()
 109 {
 110     DEFINE_STATIC_LOCAL(ScrollbarThemeChromiumMac, theme, ());
 111     return &theme;
 112 }
 113
 114 // FIXME: Get these numbers from CoreUI.
 115 static int cScrollbarThickness[] = { 15, 11 };
 116 static int cRealButtonLength[] = { 28, 21 };
 117 static int cButtonInset[] = { 14, 11 };
 118 static int cButtonHitInset[] = { 3, 2 };
 119 // cRealButtonLength - cButtonInset
 120 static int cButtonLength[] = { 14, 10 };
 121 static int cThumbMinLength[] = { 26, 20 };
 122
 123 static int cOuterButtonLength[] = { 16, 14 }; // The outer button in a double button pair is a bit bigger.
 124 static int cOuterButtonOverlap = 2;
 125
 126 static float gInitialButtonDelay = 0.5f;
 127 static float gAutoscrollButtonDelay = 0.05f;
 128 static bool gJumpOnTrackClick = false;
 129 static ScrollbarButtonsPlacement gButtonPlacement = ScrollbarButtonsDoubleEnd;
 130
 131 static void updateArrowPlacement()
 132 {
 133     NSString *buttonPlacement = [[NSUserDefaults standardUserDefaults] objectForKey:@"AppleScrollBarVariant"];
 134     if ([buttonPlacement isEqualToString:@"Single"])
 135         gButtonPlacement = ScrollbarButtonsSingle;
 136     else if ([buttonPlacement isEqualToString:@"DoubleMin"])
 137         gButtonPlacement = ScrollbarButtonsDoubleStart;
 138     else if ([buttonPlacement isEqualToString:@"DoubleBoth"])
 139         gButtonPlacement = ScrollbarButtonsDoubleBoth;
 140     else
 141         gButtonPlacement = ScrollbarButtonsDoubleEnd; // The default is ScrollbarButtonsDoubleEnd.
 142 }
 143
 144 void ScrollbarThemeChromiumMac::registerScrollbar(Scrollbar* scrollbar)
 145 {
 146     if (!gScrollbars)
 147         gScrollbars = new HashSet<Scrollbar*>;
 148     gScrollbars->add(scrollbar);
 149 }
 150
 151 void ScrollbarThemeChromiumMac::unregisterScrollbar(Scrollbar* scrollbar)
 152 {
 153     gScrollbars->remove(scrollbar);
 154     if (gScrollbars->isEmpty()) {
 155         delete gScrollbars;
 156         gScrollbars = 0;
 157     }
 158 }
 159
 160 ScrollbarThemeChromiumMac::ScrollbarThemeChromiumMac()
 161 {
 162     static bool initialized;
 163     if (!initialized) {
 164         initialized = true;
 165         [ScrollbarPrefsObserver registerAsObserver];
 166         preferencesChanged();
 167     }
 168 }
 169
 170 ScrollbarThemeChromiumMac::~ScrollbarThemeChromiumMac()
 171 {
 172 }
 173
 174 void ScrollbarThemeChromiumMac::preferencesChanged()
 175 {
 176     NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
 177     [defaults synchronize];
 178     updateArrowPlacement();
 179     gInitialButtonDelay = [defaults floatForKey:@"NSScrollerButtonDelay"];
 180     gAutoscrollButtonDelay = [defaults floatForKey:@"NSScrollerButtonPeriod"];
 181     gJumpOnTrackClick = [defaults boolForKey:@"AppleScrollerPagingBehavior"];
 182 }
 183
 184 int ScrollbarThemeChromiumMac::scrollbarThickness(ScrollbarControlSize controlSize)
 185 {
 186     return cScrollbarThickness[controlSize];
 187 }
 188
 189 double ScrollbarThemeChromiumMac::initialAutoscrollTimerDelay()
 190 {
 191     return gInitialButtonDelay;
 192 }
 193
 194 double ScrollbarThemeChromiumMac::autoscrollTimerDelay()
 195 {
 196     return gAutoscrollButtonDelay;
 197 }
 198
 199 ScrollbarButtonsPlacement ScrollbarThemeChromiumMac::buttonsPlacement() const
 200 {
 201     return gButtonPlacement;
 202 }
 203
 204 bool ScrollbarThemeChromiumMac::hasButtons(Scrollbar* scrollbar)
 205 {
 206     return scrollbar->enabled() && (scrollbar->orientation() == HorizontalScrollbar ?
 207              scrollbar->width() :
 208              scrollbar->height()) >= 2 * (cRealButtonLength[scrollbar->controlSize()] - cButtonHitInset[scrollbar->controlSize()]);
 209 }
 210
 211 bool ScrollbarThemeChromiumMac::hasThumb(Scrollbar* scrollbar)
 212 {
 213     return scrollbar->enabled() && (scrollbar->orientation() == HorizontalScrollbar ?
 214              scrollbar->width() :
 215              scrollbar->height()) >= 2 * cButtonInset[scrollbar->controlSize()] + cThumbMinLength[scrollbar->controlSize()] + 1;
 216 }
 217
 218 static IntRect buttonRepaintRect(const IntRect& buttonRect, ScrollbarOrientation orientation, ScrollbarControlSize controlSize, bool start)
 219 {
 220     IntRect paintRect(buttonRect);
 221     if (orientation == HorizontalScrollbar) {
 222         paintRect.setWidth(cRealButtonLength[controlSize]);
 223         if (!start)
 224             paintRect.setX(buttonRect.x() - (cRealButtonLength[controlSize] - buttonRect.width()));
 225     } else {
 226         paintRect.setHeight(cRealButtonLength[controlSize]);
 227         if (!start)
 228             paintRect.setY(buttonRect.y() - (cRealButtonLength[controlSize] - buttonRect.height()));
 229     }
 230
 231     return paintRect;
 232 }
 233
 234 IntRect ScrollbarThemeChromiumMac::backButtonRect(Scrollbar* scrollbar, ScrollbarPart part, bool painting)
 235 {
 236     IntRect result;
 237
 238     if (part == BackButtonStartPart && (buttonsPlacement() == ScrollbarButtonsNone || buttonsPlacement() == ScrollbarButtonsDoubleEnd))
 239         return result;
 240
 241     if (part == BackButtonEndPart && (buttonsPlacement() == ScrollbarButtonsNone || buttonsPlacement() == ScrollbarButtonsDoubleStart || buttonsPlacement() == ScrollbarButtonsSingle))
 242         return result;
 243
 244     int thickness = scrollbarThickness(scrollbar->controlSize());
 245     bool outerButton = part == BackButtonStartPart && (buttonsPlacement() == ScrollbarButtonsDoubleStart || buttonsPlacement() == ScrollbarButtonsDoubleBoth);
 246     if (outerButton) {
 247         if (scrollbar->orientation() == HorizontalScrollbar)
 248             result = IntRect(scrollbar->x(), scrollbar->y(), cOuterButtonLength[scrollbar->controlSize()] + painting ? cOuterButtonOverlap : 0, thickness);
 249         else
 250             result = IntRect(scrollbar->x(), scrollbar->y(), thickness, cOuterButtonLength[scrollbar->controlSize()] + painting ? cOuterButtonOverlap : 0);
 251         return result;
 252     }
 253
 254     // Our repaint rect is slightly larger, since we are a button that is adjacent to the track.
 255     if (scrollbar->orientation() == HorizontalScrollbar) {
 256         int start = part == BackButtonStartPart ? scrollbar->x() : scrollbar->x() + scrollbar->width() - cOuterButtonLength[scrollbar->controlSize()] - cButtonLength[scrollbar->controlSize()];
 257         result = IntRect(start, scrollbar->y(), cButtonLength[scrollbar->controlSize()], thickness);
 258     } else {
 259         int start = part == BackButtonStartPart ? scrollbar->y() : scrollbar->y() + scrollbar->height() - cOuterButtonLength[scrollbar->controlSize()] - cButtonLength[scrollbar->controlSize()];
 260         result = IntRect(scrollbar->x(), start, thickness, cButtonLength[scrollbar->controlSize()]);
 261     }
 262
 263     if (painting)
 264         return buttonRepaintRect(result, scrollbar->orientation(), scrollbar->controlSize(), part == BackButtonStartPart);
 265     return result;
 266 }
 267
 268 IntRect ScrollbarThemeChromiumMac::forwardButtonRect(Scrollbar* scrollbar, ScrollbarPart part, bool painting)
 269 {
 270     IntRect result;
 271
 272     if (part == ForwardButtonEndPart && (buttonsPlacement() == ScrollbarButtonsNone || buttonsPlacement() == ScrollbarButtonsDoubleStart))
 273         return result;
 274
 275     if (part == ForwardButtonStartPart && (buttonsPlacement() == ScrollbarButtonsNone || buttonsPlacement() == ScrollbarButtonsDoubleEnd || buttonsPlacement() == ScrollbarButtonsSingle))
 276         return result;
 277
 278     int thickness = scrollbarThickness(scrollbar->controlSize());
 279     int outerButtonLength = cOuterButtonLength[scrollbar->controlSize()];
 280     int buttonLength = cButtonLength[scrollbar->controlSize()];
 281
 282     bool outerButton = part == ForwardButtonEndPart && (buttonsPlacement() == ScrollbarButtonsDoubleEnd || buttonsPlacement() == ScrollbarButtonsDoubleBoth);
 283     if (outerButton) {
 284         if (scrollbar->orientation() == HorizontalScrollbar) {
 285             result = IntRect(scrollbar->x() + scrollbar->width() - outerButtonLength, scrollbar->y(), outerButtonLength, thickness);
 286             if (painting)
 287                 result.inflateX(cOuterButtonOverlap);
 288         } else {
 289             result = IntRect(scrollbar->x(), scrollbar->y() + scrollbar->height() - outerButtonLength, thickness, outerButtonLength);
 290             if (painting)
 291                 result.inflateY(cOuterButtonOverlap);
 292         }
 293         return result;
 294     }
 295
 296     if (scrollbar->orientation() == HorizontalScrollbar) {
 297         int start = part == ForwardButtonEndPart ? scrollbar->x() + scrollbar->width() - buttonLength : scrollbar->x() + outerButtonLength;
 298         result = IntRect(start, scrollbar->y(), buttonLength, thickness);
 299     } else {
 300         int start = part == ForwardButtonEndPart ? scrollbar->y() + scrollbar->height() - buttonLength : scrollbar->y() + outerButtonLength;
 301         result = IntRect(scrollbar->x(), start, thickness, buttonLength);
 302     }
 303     if (painting)
 304         return buttonRepaintRect(result, scrollbar->orientation(), scrollbar->controlSize(), part == ForwardButtonStartPart);
 305     return result;
 306 }
 307
 308 IntRect ScrollbarThemeChromiumMac::trackRect(Scrollbar* scrollbar, bool painting)
 309 {
 310     if (painting || !hasButtons(scrollbar))
 311         return scrollbar->frameRect();
 312
 313     IntRect result;
 314     int thickness = scrollbarThickness(scrollbar->controlSize());
 315     int startWidth = 0;
 316     int endWidth = 0;
 317     int outerButtonLength = cOuterButtonLength[scrollbar->controlSize()];
 318     int buttonLength = cButtonLength[scrollbar->controlSize()];
 319     int doubleButtonLength = outerButtonLength + buttonLength;
 320     switch (buttonsPlacement()) {
 321         case ScrollbarButtonsSingle:
 322             startWidth = buttonLength;
 323             endWidth = buttonLength;
 324             break;
 325         case ScrollbarButtonsDoubleStart:
 326             startWidth = doubleButtonLength;
 327             break;
 328         case ScrollbarButtonsDoubleEnd:
 329             endWidth = doubleButtonLength;
 330             break;
 331         case ScrollbarButtonsDoubleBoth:
 332             startWidth = doubleButtonLength;
 333             endWidth = doubleButtonLength;
 334             break;
 335         default:
 336             break;
 337     }
 338
 339     int totalWidth = startWidth + endWidth;
 340     if (scrollbar->orientation() == HorizontalScrollbar)
 341         return IntRect(scrollbar->x() + startWidth, scrollbar->y(), scrollbar->width() - totalWidth, thickness);
 342     return IntRect(scrollbar->x(), scrollbar->y() + startWidth, thickness, scrollbar->height() - totalWidth);
 343 }
 344
 345 int ScrollbarThemeChromiumMac::minimumThumbLength(Scrollbar* scrollbar)
 346 {
 347     return cThumbMinLength[scrollbar->controlSize()];
 348 }
 349
 350 bool ScrollbarThemeChromiumMac::shouldCenterOnThumb(Scrollbar*, const PlatformMouseEvent& evt)
 351 {
 352     if (evt.button() != LeftButton)
 353         return false;
 354     if (gJumpOnTrackClick)
 355         return !evt.altKey();
 356     return evt.altKey();
 357 }
 358
 359 static int scrollbarPartToHIPressedState(ScrollbarPart part)
 360 {
 361     switch (part) {
 362         case BackButtonStartPart:
 363             return kThemeTopOutsideArrowPressed;
 364         case BackButtonEndPart:
 365             return kThemeTopOutsideArrowPressed; // This does not make much sense.  For some reason the outside constant is required.
 366         case ForwardButtonStartPart:
 367             return kThemeTopInsideArrowPressed;
 368         case ForwardButtonEndPart:
 369             return kThemeBottomOutsideArrowPressed;
 370         case ThumbPart:
 371             return kThemeThumbPressed;
 372         default:
 373             return 0;
 374     }
 375 }
 376
 377 #if USE_WEB_THEME_ENGINE_TO_PAINT_THUMB
 378 static ChromiumBridge::ThemePaintState scrollbarStateToThemeState(Scrollbar* scrollbar) {
 379     if (!scrollbar->enabled())
 380         return ChromiumBridge::StateDisabled;
 381     if (!scrollbar->client()->isActive())
 382         return ChromiumBridge::StateInactive;
 383     if (scrollbar->pressedPart() == ThumbPart)
 384         return ChromiumBridge::StatePressed;
 385
 386     return ChromiumBridge::StateActive;
 387 }
 388 #endif // USE_WEB_THEME_ENGINE_TO_PAINT_THUMB
 389
 390 bool ScrollbarThemeChromiumMac::paint(Scrollbar* scrollbar, GraphicsContext* context, const IntRect& damageRect)
 391 {
 392     HIThemeTrackDrawInfo trackInfo;
 393     trackInfo.version = 0;
 394     trackInfo.kind = scrollbar->controlSize() == RegularScrollbar ? kThemeMediumScrollBar : kThemeSmallScrollBar;
 395     trackInfo.bounds = scrollbar->frameRect();
 396     trackInfo.min = 0;
 397     trackInfo.max = scrollbar->maximum();
 398     trackInfo.value = scrollbar->currentPos();
 399     trackInfo.trackInfo.scrollbar.viewsize = scrollbar->visibleSize();
 400     trackInfo.attributes = 0;
 401     if (scrollbar->orientation() == HorizontalScrollbar)
 402         trackInfo.attributes |= kThemeTrackHorizontal;
 403
 404     if (!scrollbar->enabled())
 405         trackInfo.enableState = kThemeTrackDisabled;
 406     else
 407         trackInfo.enableState = scrollbar->client()->isActive() ? kThemeTrackActive : kThemeTrackInactive;
 408
 409     if (!hasButtons(scrollbar))
 410         trackInfo.enableState = kThemeTrackNothingToScroll;
 411     trackInfo.trackInfo.scrollbar.pressState = scrollbarPartToHIPressedState(scrollbar->pressedPart());
 412
 413     CGAffineTransform currentCTM = CGContextGetCTM(context->platformContext());
 414
 415     // The Aqua scrollbar is buggy when rotated and scaled.  We will just draw into a bitmap if we detect a scale or rotation.
 416     bool canDrawDirectly = currentCTM.a == 1.0f && currentCTM.b == 0.0f && currentCTM.c == 0.0f && (currentCTM.d == 1.0f || currentCTM.d == -1.0f);
 417     GraphicsContext* drawingContext = context;
 418     OwnPtr<ImageBuffer> imageBuffer;
 419     if (!canDrawDirectly) {
 420         trackInfo.bounds = IntRect(IntPoint(), scrollbar->frameRect().size());
 421
 422         IntRect bufferRect(scrollbar->frameRect());
 423         bufferRect.intersect(damageRect);
 424         bufferRect.move(-scrollbar->frameRect().x(), -scrollbar->frameRect().y());
 425
 426         imageBuffer = ImageBuffer::create(bufferRect.size());
 427         if (!imageBuffer)
 428             return true;
 429
 430         drawingContext = imageBuffer->context();
 431     }
 432
 433     // Draw thumbless.
 434     HIThemeDrawTrack(&trackInfo, 0, drawingContext->platformContext(), kHIThemeOrientationNormal);
 435
 436     Vector<IntRect> tickmarks;
 437     scrollbar->client()->getTickmarks(tickmarks);
 438     if (scrollbar->orientation() == VerticalScrollbar && tickmarks.size()) {
 439         drawingContext->save();
 440         drawingContext->setShouldAntialias(false);
 441         drawingContext->setStrokeColor(Color(0xCC, 0xAA, 0x00, 0xFF), ColorSpaceDeviceRGB);
 442         drawingContext->setFillColor(Color(0xFF, 0xDD, 0x00, 0xFF), ColorSpaceDeviceRGB);
 443
 444         IntRect thumbArea = trackRect(scrollbar, false);
 445         if (!canDrawDirectly) {
 446             thumbArea.setX(0);
 447             thumbArea.setY(0);
 448         }
 449         // The ends are rounded and the thumb doesn't go there.
 450         thumbArea.inflateY(-thumbArea.width());
 451
 452         for (Vector<IntRect>::const_iterator i = tickmarks.begin(); i != tickmarks.end(); ++i) {
 453             // Calculate how far down (in %) the tick-mark should appear.
 454             const float percent = static_cast<float>(i->y()) / scrollbar->totalSize();
 455             if (percent < 0.0 || percent > 1.0)
 456               continue;
 457
 458             // Calculate how far down (in pixels) the tick-mark should appear.
 459             const int yPos = static_cast<int>((thumbArea.topLeft().y() + (thumbArea.height() * percent))) & ~1;
 460
 461             // Paint.
 462             const int indent = 2;
 463             FloatRect tickRect(thumbArea.topLeft().x() + indent, yPos, thumbArea.width() - 2 * indent - 1, 2);
 464             drawingContext->fillRect(tickRect);
 465             drawingContext->strokeRect(tickRect, 1);
 466         }
 467
 468         drawingContext->restore();
 469     }
 470
 471     if (hasThumb(scrollbar)) {
 472 #if USE_WEB_THEME_ENGINE_TO_PAINT_THUMB
 473         ChromiumBridge::ThemePaintScrollbarInfo scrollbarInfo;
 474         scrollbarInfo.orientation = scrollbar->orientation() == HorizontalScrollbar ? ChromiumBridge::ScrollbarOrientationHorizontal : ChromiumBridge::ScrollbarOrientationVertical;
 475         scrollbarInfo.parent = scrollbar->parent()->isFrameView() && static_cast<FrameView*>(scrollbar->parent())->isScrollViewScrollbar(scrollbar) ? ChromiumBridge::ScrollbarParentScrollView : ChromiumBridge::ScrollbarParentRenderLayer;
 476         scrollbarInfo.maxValue = scrollbar->maximum();
 477         scrollbarInfo.currentValue = scrollbar->currentPos();
 478         scrollbarInfo.visibleSize = scrollbar->visibleSize();
 479         scrollbarInfo.totalSize = scrollbar->totalSize();
 480
 481         ChromiumBridge::paintScrollbarThumb(
 482             drawingContext,
 483             scrollbarStateToThemeState(scrollbar),
 484             scrollbar->controlSize() == RegularScrollbar ? ChromiumBridge::SizeRegular : ChromiumBridge::SizeSmall,
 485             scrollbar->frameRect(),
 486             scrollbarInfo);
 487 #else
 488         trackInfo.attributes |= (kThemeTrackShowThumb | kThemeTrackHideTrack);
 489         HIThemeDrawTrack(&trackInfo, 0, drawingContext->platformContext(), kHIThemeOrientationNormal);
 490 #endif
 491     }
 492
 493     if (!canDrawDirectly)
 494         context->drawImageBuffer(imageBuffer.get(), ColorSpaceDeviceRGB, scrollbar->frameRect().location());
 495
 496     return true;
 497 }
 498
 499 }
 500