Expose locks for CopyFromCompositingSurface/CopyFromBackingStore API

content/browser/renderer_host/render_widget_host_view_base.cc

 // 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.
 
 #include "content/browser/renderer_host/render_widget_host_view_base.h"
 
 #include "base/logging.h"
 #include "content/browser/accessibility/browser_accessibility_manager.h"
 #include "content/browser/gpu/gpu_data_manager_impl.h"
 #include "content/browser/renderer_host/input/synthetic_gesture_target_base.h"
@@ skipping 575 matching lines @@
 }
 
 uint32 RenderWidgetHostViewBase::RendererFrameNumber() {
   return renderer_frame_number_;
 }
 
 void RenderWidgetHostViewBase::DidReceiveRendererFrame() {
   ++renderer_frame_number_;
 }
 
+void RenderWidgetHostViewBase::LockSurfaceForCopy() {}

[jam, 2014/02/26 00:09:54]

where is the implementation of this?

+
+void RenderWidgetHostViewBase::UnlockSurfaceForCopy() {}
+
 void RenderWidgetHostViewBase::FlushInput() {
   RenderWidgetHostImpl* impl = NULL;
   if (GetRenderWidgetHost())
     impl = RenderWidgetHostImpl::From(GetRenderWidgetHost());
   if (!impl)
     return;
   impl->FlushInput();
 }
 
 }  // namespace content