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

content/browser/gpu/gpu_process_host_ui_shim.cc

Index: content/browser/gpu/gpu_process_host_ui_shim.cc
diff --git a/content/browser/gpu/gpu_process_host_ui_shim.cc b/content/browser/gpu/gpu_process_host_ui_shim.cc
index 53208f0db3e3ab944dc9a64411be8643a730a202..ea9129dca34b9033dd6c1b24aaa095e10da515e8 100644
--- a/content/browser/gpu/gpu_process_host_ui_shim.cc
+++ b/content/browser/gpu/gpu_process_host_ui_shim.cc
@@ -410,11 +410,16 @@ void GpuProcessHostUIShim::OnAcceleratedSurfaceSuspend(int32 surface_id) {
 
 void GpuProcessHostUIShim::OnAcceleratedSurfaceRelease(
     const GpuHostMsg_AcceleratedSurfaceRelease_Params& params) {
+  bool success = false;
+
   RenderWidgetHostViewPort* view = GetRenderWidgetHostViewFromSurfaceID(
       params.surface_id);
-  if (!view)
-    return;
-  view->AcceleratedSurfaceRelease(params.identifier);
+  if (view)
+    success = view->AcceleratedSurfaceRelease(params.identifier);
+
+  Send(new AcceleratedSurfaceMsg_ReleaseACK(params.route_id,
+                                            params.identifier,
+                                            success));
 }
 
 #endif