Add a flag to allow renderer to use software compositor when GL compositor doesn't work.

content/renderer/render_widget.h

 // Copyright (c) 2012 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.
 
 #ifndef CONTENT_RENDERER_RENDER_WIDGET_H_
 #define CONTENT_RENDERER_RENDER_WIDGET_H_
 
 #include <deque>
 #include <map>
 
@@ skipping 156 matching lines @@
   // Fills in a GpuRenderingStats struct containing information about
   // GPU rendering, e.g. count of texture uploads performed, time spent
   // uploading.
   // This call is relatively expensive as it blocks on the GPU process
   bool GetGpuRenderingStats(GpuRenderingStats*) const;
 
   void GetBrowserRenderingStats(BrowserRenderingStats* stats);
 
   RenderWidgetCompositor* compositor() const;
 
-  virtual scoped_ptr<cc::OutputSurface> CreateOutputSurface();
+  virtual scoped_ptr<cc::OutputSurface> CreateOutputSurface(bool fallback);
 
   // Callback for use with BeginSmoothScroll.
   typedef base::Callback<void()> SmoothScrollCompletionCallback;
 
   // Directs the host to begin a smooth scroll. This scroll should have the same
   // performance characteristics as a user-initiated scroll. Returns an ID of
   // the scroll gesture. |mouse_event_x| and |mouse_event_y| are expected to be
   // in local DIP coordinates.
   void BeginSmoothScroll(bool scroll_down,
                          const SmoothScrollCompletionCallback& callback,
@@ skipping 530 matching lines @@
   uint32 next_output_surface_id_;
 
   base::WeakPtrFactory<RenderWidget> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderWidget);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_RENDER_WIDGET_H_