Set up clip and scroll parents on the blink side.

Source/core/platform/graphics/GraphicsLayer.cpp

 /*
  * Copyright (C) 2009 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 340 matching lines @@
 
     m_offsetFromRenderer = offset;
 
     // If the compositing layer offset changes, we need to repaint.
     if (shouldSetNeedsDisplay == SetNeedsDisplay)
         setNeedsDisplay();
 }
 
 void GraphicsLayer::paintGraphicsLayerContents(GraphicsContext& context, const IntRect& clip)
 {
-    if (m_client)
+    if (m_client) {
+        TRACE_EVENT_INSTANT2("core,painting", "GraphicsLayer::paintGraphicsLayerContents",

[enne (OOO), 2013/08/22 20:54:30]

I think we already are tracing this from the compositor side.

+            "width", clip.width(), "height", clip.height());
+
         m_client->paintContents(this, context, m_paintingPhase, clip);
+    }
 }
 
 String GraphicsLayer::animationNameForTransition(AnimatedPropertyID property)
 {
     // | is not a valid identifier character in CSS, so this can never conflict with a keyframe identifier.
     StringBuilder id;
     id.appendLiteral("-|transition");
     id.appendNumber(static_cast<int>(property));
     id.append('-');
     return id.toString();
@@ skipping 922 matching lines @@
         m_client->notifyAnimationStarted(this, startTime);
 }
 
 void GraphicsLayer::notifyAnimationFinished(double)
 {
     // Do nothing.
 }
 
 void GraphicsLayer::didScroll()
 {
+    TRACE_EVENT1(
+        "impl-scroll",
+        "GraphicsLayer::didScroll",
+        "layerId",
+        m_layer->layer()->id());
+
     if (m_scrollableArea)
         m_scrollableArea->scrollToOffsetWithoutAnimation(m_scrollableArea->minimumScrollPosition() + toIntSize(m_layer->layer()->scrollPosition()));
 }
 
 } // namespace WebCore
 
 #ifndef NDEBUG
 void showGraphicsLayerTree(const WebCore::GraphicsLayer* layer)
 {
     if (!layer)
         return;
 
     String output = layer->layerTreeAsText(WebCore::LayerTreeIncludesDebugInfo);
     fprintf(stderr, "%s\n", output.utf8().data());
 }
 #endif