Remove mainthread overhang painting code

Source/web/ChromeClientImpl.cpp

 /*
  * Copyright (C) 2009 Google Inc. All rights reserved.
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
  *
  * 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.
@@ skipping 647 matching lines @@
     // FIXME: delete these lines once Chrome only uses the frame client interface, above.
     if (m_webView->client())
         m_webView->client()->postAccessibilityEvent(WebAXObject(obj), toWebAXEvent(notification));
 }
 
 String ChromeClientImpl::acceptLanguages()
 {
     return m_webView->client()->acceptLanguages();
 }
 
-bool ChromeClientImpl::paintCustomOverhangArea(GraphicsContext* context, const IntRect& horizontalOverhangArea, const IntRect& verticalOverhangArea, const IntRect& dirtyRect)
-{
-    LocalFrame* frame = m_webView->mainFrameImpl()->frame();
-    WebPluginContainerImpl* pluginContainer = WebLocalFrameImpl::pluginContainerFromFrame(frame);
-    if (pluginContainer)
-        return pluginContainer->paintCustomOverhangArea(context, horizontalOverhangArea, verticalOverhangArea, dirtyRect);
-    return false;
-}
-
 GraphicsLayerFactory* ChromeClientImpl::graphicsLayerFactory() const
 {
     return m_webView->graphicsLayerFactory();
 }
 
 void ChromeClientImpl::attachRootGraphicsLayer(GraphicsLayer* rootLayer, LocalFrame* localRoot)
 {
     // FIXME: For top-level frames we still use the WebView as a WebWidget. This special
     // case will be removed when top-level frames get WebFrameWidgets.
     if (localRoot->isMainFrame()) {
@@ skipping 232 matching lines @@
     if (m_webView->rootGraphicsLayer() && m_webView->layerTreeView())
         m_webView->page()->frameHost().pinchViewport().registerLayersWithTreeView(m_webView->layerTreeView());
 }
 
 void ChromeClientImpl::didUpdateTopControls() const
 {
     m_webView->didUpdateTopControls();
 }
 
 } // namespace blink