Turn off computation of the interest rect in cc in synchronized paint mode.

third_party/WebKit/Source/platform/graphics/ContentLayerDelegate.cpp

 /*
  * Copyright (C) 2012 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
  *     notice, this list of conditions and the following disclaimer in the
@@ skipping 23 matching lines @@
 #include "platform/graphics/GraphicsContext.h"
 #include "platform/graphics/paint/PaintArtifactToSkCanvas.h"
 #include "platform/graphics/paint/PaintController.h"
 #include "platform/transforms/AffineTransform.h"
 #include "platform/transforms/TransformationMatrix.h"
 #include "public/platform/WebDisplayItemList.h"
 #include "public/platform/WebFloatRect.h"
 #include "public/platform/WebRect.h"
 #include "third_party/skia/include/core/SkCanvas.h"
 #include "third_party/skia/include/core/SkPicture.h"
+#include "ui/gfx/geometry/rect.h"
 
 namespace blink {
 
 ContentLayerDelegate::ContentLayerDelegate(GraphicsContextPainter* painter)
     : m_painter(painter)
 {
 }
 
 ContentLayerDelegate::~ContentLayerDelegate()
 {
@@ skipping 20 matching lines @@
         // one big flat SkPicture.
         SkRect skBounds = SkRect::MakeXYWH(bounds.x, bounds.y, bounds.width, bounds.height);
         RefPtr<SkPicture> picture = paintArtifactToSkPicture(artifact, skBounds);
         // TODO(wkorman): Pass actual visual rect with the drawing item.
         list->appendDrawingItem(IntRect(), picture.get());
         return;
     }
     artifact.appendToWebDisplayItemList(list);
 }
 
+gfx::Rect ContentLayerDelegate::paintableRegion()
+{
+    IntRect interestRect = m_painter->interestRect();
+    return gfx::Rect(interestRect.x(), interestRect.y(), interestRect.width(), interestRect.height());
+}
+
 void ContentLayerDelegate::paintContents(
     WebDisplayItemList* webDisplayItemList, const WebRect& clip,
     WebContentLayerClient::PaintingControlSetting paintingControl)
 {
     TRACE_EVENT1("blink,benchmark", "ContentLayerDelegate::paintContents", "clip_rect", toTracedValue(clip));
 
     PaintController* paintController = m_painter->paintController();
     ASSERT(paintController);
     paintController->setDisplayItemConstructionIsDisabled(
         paintingControl == WebContentLayerClient::DisplayListConstructionDisabled);
@@ skipping 15 matching lines @@
     paintController->commitNewDisplayItems();
     paintArtifactToWebDisplayItemList(webDisplayItemList, paintController->paintArtifact(), clip);
 }
 
 size_t ContentLayerDelegate::approximateUnsharedMemoryUsage() const
 {
     return m_painter->paintController()->approximateUnsharedMemoryUsage();
 }
 
 } // namespace blink