content: Remove Lock/Unlock CompositingSurface API from RWH.

content/browser/frame_host/render_widget_host_view_child_frame.h

Index: content/browser/frame_host/render_widget_host_view_child_frame.h
diff --git a/content/browser/frame_host/render_widget_host_view_child_frame.h b/content/browser/frame_host/render_widget_host_view_child_frame.h
index c509b0124bad89eef99eb15dc0693768729bc42e..2e72df3a2b01962d6e1b5f4cd9adc194e55cf049 100644
--- a/content/browser/frame_host/render_widget_host_view_child_frame.h
+++ b/content/browser/frame_host/render_widget_host_view_child_frame.h
@@ -156,10 +156,6 @@ class CONTENT_EXPORT RenderWidgetHostViewChildFrame
   void StopSpeaking() override;
 #endif  // defined(OS_MACOSX)
 
-  // RenderWidgetHostViewBase implementation.
-  void LockCompositingSurface() override;
-  void UnlockCompositingSurface() override;
-
   InputEventAckState FilterInputEvent(
       const blink::WebInputEvent& input_event) override;
   BrowserAccessibilityManager* CreateBrowserAccessibilityManager(