Drop frontbuffers with ui-use-gpu-process, synchronized with browser, decoupled from backbuffer dro…

content/browser/renderer_host/render_widget_host_impl.h

Index: content/browser/renderer_host/render_widget_host_impl.h
diff --git a/content/browser/renderer_host/render_widget_host_impl.h b/content/browser/renderer_host/render_widget_host_impl.h
index 790de8f1aeca5757cbc5acde6eb71ff02ab15ae9..ec7897029fcd3c291c8e35a10f1d8787f6277f87 100644
--- a/content/browser/renderer_host/render_widget_host_impl.h
+++ b/content/browser/renderer_host/render_widget_host_impl.h
@@ -152,6 +152,7 @@ class CONTENT_EXPORT RenderWidgetHostImpl : virtual public RenderWidgetHost,
   // having been hidden.
   void WasHidden();
   void WasRestored();
+  bool IsVisible() const { return !is_hidden_; }
 
   // Called to notify the RenderWidget that its associated native window got
   // focused.
@@ -356,6 +357,19 @@ class CONTENT_EXPORT RenderWidgetHostImpl : virtual public RenderWidgetHost,
   static void AcknowledgeSwapBuffers(int32 route_id, int gpu_host_id);
   static void AcknowledgePostSubBuffer(int32 route_id, int gpu_host_id);
 
+#if defined(USE_AURA)
+  // Called by the view in response to AcceleratedSurfaceRequestReleaseFront.
+  static void AcknowledgeRequestReleaseFront(int request_id,
+                                             int retry_count,
+                                             bool was_released,
+                                             int32 route_id,
+                                             int gpu_host_id);
+  // Called by the view in response to visibility changes.
+  static void SendFrontSurfaceIsProtected(bool is_protected,
+                                          int32 route_id,
+                                          int gpu_host_id);
+#endif
+
   // Signals that the compositing surface was updated, e.g. after a lost context
   // event.
   void CompositingSurfaceUpdated();