Set up clip and scroll parents on the blink side.

Source/web/WebViewImpl.cpp

 /*
  * Copyright (C) 2011, 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 3913 matching lines @@
             m_client->didDeactivateCompositor();
             m_compositorCreationFailed = true;
         }
     }
     if (page())
         page()->mainFrame()->view()->setClipsRepaints(!m_isAcceleratedCompositingActive);
 }
 
 void WebViewImpl::updateMainFrameScrollPosition(const IntPoint& scrollPosition, bool programmaticScroll)
 {
+    TRACE_EVENT1("impl-scroll",
+        "WebViewImpl::updateMainFrameScrollPosition",
+        "programmatic", programmaticScroll);
+
     FrameView* frameView = page()->mainFrame()->view();
     if (!frameView)
         return;
 
     if (frameView->scrollPosition() == scrollPosition)
         return;
 
     bool oldProgrammaticScroll = frameView->inProgrammaticScroll();
     frameView->setInProgrammaticScroll(programmaticScroll);
     frameView->notifyScrollPositionChanged(scrollPosition);
     frameView->setInProgrammaticScroll(oldProgrammaticScroll);
 }
 
 void WebViewImpl::applyScrollAndScale(const WebSize& scrollDelta, float pageScaleDelta)
 {
     if (!mainFrameImpl() || !mainFrameImpl()->frameView())
         return;
 
     if (pageScaleDelta == 1) {
-        TRACE_EVENT_INSTANT2("webkit", "WebViewImpl::applyScrollAndScale::scrollBy", "x", scrollDelta.width, "y", scrollDelta.height);
+        TRACE_EVENT_INSTANT2("webkit,impl-scroll", "WebViewImpl::applyScrollAndScale::scrollBy", "x", scrollDelta.width, "y", scrollDelta.height);
         WebSize webScrollOffset = mainFrame()->scrollOffset();
         IntPoint scrollOffset(webScrollOffset.width + scrollDelta.width, webScrollOffset.height + scrollDelta.height);
         updateMainFrameScrollPosition(scrollOffset, false);
     } else {
         // The page scale changed, so apply a scale and scroll in a single
         // operation.
         WebSize scrollOffset = mainFrame()->scrollOffset();
         scrollOffset.width += scrollDelta.width;
         scrollOffset.height += scrollDelta.height;
 
@@ skipping 121 matching lines @@
 }
 
 bool WebViewImpl::shouldDisableDesktopWorkarounds()
 {
     ViewportArguments arguments = mainFrameImpl()->frame()->document()->viewportArguments();
     return arguments.width == ViewportArguments::ValueDeviceWidth || !arguments.userZoom
         || (arguments.minZoom == arguments.maxZoom && arguments.minZoom != ViewportArguments::ValueAuto);
 }
 
 } // namespace WebKit