Expose locks for CopyFromCompositingSurface/CopyFromBackingStore API

content/browser/renderer_host/render_widget_host_view_base.cc

Index: content/browser/renderer_host/render_widget_host_view_base.cc
diff --git a/content/browser/renderer_host/render_widget_host_view_base.cc b/content/browser/renderer_host/render_widget_host_view_base.cc
index fddb27880b31168bd9e863cb2a004cff96552c40..78da83edd786f10bad4afe805c2a976dbd620d0e 100644
--- a/content/browser/renderer_host/render_widget_host_view_base.cc
+++ b/content/browser/renderer_host/render_widget_host_view_base.cc
@@ -593,6 +593,14 @@ void RenderWidgetHostViewBase::DidReceiveRendererFrame() {
   ++renderer_frame_number_;
 }
 
+void RenderWidgetHostViewBase::LockSurface() {
+  NOTIMPLEMENTED();
+}
+
+void RenderWidgetHostViewBase::UnlockSurface() {
+  NOTIMPLEMENTED();
+}
+
 void RenderWidgetHostViewBase::FlushInput() {
   RenderWidgetHostImpl* impl = NULL;
   if (GetRenderWidgetHost())