Change Widget subclasses to use a CullRect instead of an IntRect for painting.

third_party/WebKit/Source/core/layout/compositing/PaintLayerCompositor.cpp

 /*
  * Copyright (C) 2009, 2010 Apple 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 40 matching lines @@
 #include "core/loader/FrameLoaderClient.h"
 #include "core/page/ChromeClient.h"
 #include "core/page/Page.h"
 #include "core/page/scrolling/ScrollingCoordinator.h"
 #include "core/paint/FramePainter.h"
 #include "core/paint/TransformRecorder.h"
 #include "platform/RuntimeEnabledFeatures.h"
 #include "platform/ScriptForbiddenScope.h"
 #include "platform/TraceEvent.h"
 #include "platform/graphics/GraphicsLayer.h"
+#include "platform/graphics/paint/CullRect.h"
 #include "platform/graphics/paint/DrawingRecorder.h"
 #include "platform/graphics/paint/PaintController.h"
 #include "platform/graphics/paint/TransformDisplayItem.h"
 #include "public/platform/Platform.h"
 
 namespace blink {
 
 PaintLayerCompositor::PaintLayerCompositor(LayoutView& layoutView)
     : m_layoutView(layoutView)
     , m_compositingReasonFinder(layoutView)
@@ skipping 718 matching lines @@
 
     // Frame scrollbars are painted in the space of the containing frame, not the local space of the scrollbar.
     const IntPoint& paintOffset = scrollbar->frameRect().location();
     IntRect transformedClip = clip;
     transformedClip.moveBy(paintOffset);
 
     AffineTransform translation;
     translation.translate(-paintOffset.x(), -paintOffset.y());
     TransformRecorder transformRecorder(context, *scrollbar, translation);
 
-    scrollbar->paint(&context, transformedClip);
+    scrollbar->paint(&context, CullRect(transformedClip));
 }
 
 void PaintLayerCompositor::paintContents(const GraphicsLayer* graphicsLayer, GraphicsContext& context, GraphicsLayerPaintingPhase, const IntRect& clip) const
 {
     if (graphicsLayer == layerForHorizontalScrollbar())
         paintScrollbar(m_layoutView.frameView()->horizontalScrollbar(), context, clip);
     else if (graphicsLayer == layerForVerticalScrollbar())
         paintScrollbar(m_layoutView.frameView()->verticalScrollbar(), context, clip);
     else if (graphicsLayer == layerForScrollCorner())
         FramePainter(*m_layoutView.frameView()).paintScrollCorner(&context, clip);
@@ skipping 394 matching lines @@
     } else if (graphicsLayer == m_scrollLayer.get()) {
         name = "Frame Scrolling Layer";
     } else {
         ASSERT_NOT_REACHED();
     }
 
     return name;
 }
 
 } // namespace blink