Add command line switch for enabling threaded compositing

content/renderer/render_view.cc

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/renderer/render_view.h"
 
 #include <algorithm>
 #include <cmath>
 #include <string>
 #include <vector>
@@ skipping 3986 matching lines @@
   // Inform plugins that their container is now visible.
   std::set<WebPluginDelegateProxy*>::iterator plugin_it;
   for (plugin_it = plugin_delegates_.begin();
        plugin_it != plugin_delegates_.end(); ++plugin_it) {
     (*plugin_it)->SetContainerVisibility(true);
   }
 #endif  // OS_MACOSX
 }
 
 bool RenderView::SupportsAsynchronousSwapBuffers() {
+  if (WebWidgetHandlesCompositorScheduling())
+    return false;
+
   WebKit::WebGraphicsContext3D* context = webview()->graphicsContext3D();
   if (!context)
     return false;
   std::string extensions(context->getRequestableExtensionsCHROMIUM().utf8());
   return extensions.find("GL_CHROMIUM_swapbuffers_complete_callback") !=
       std::string::npos;
 }
 
 void RenderView::OnSetFocus(bool enable) {
   RenderWidget::OnSetFocus(enable);
@@ skipping 440 matching lines @@
   pepper_delegate_.OnLockMouseACK(succeeded);
 }
 
 void RenderView::OnMouseLockLost() {
   pepper_delegate_.OnMouseLockLost();
 }
 
 bool RenderView::WebWidgetHandlesCompositorScheduling() const {
   return webview()->settings()->useThreadedCompositor();
 }