Mac ÜC: Enable back-pressure for the browser compositor

content/browser/compositor/gpu_process_transport_factory.cc

Index: content/browser/compositor/gpu_process_transport_factory.cc
diff --git a/content/browser/compositor/gpu_process_transport_factory.cc b/content/browser/compositor/gpu_process_transport_factory.cc
index 1f8b3c022f0cd3ab502a07f5d3869744ab430892..179909f6aafc8ee9549d24863707c9f8819f93a5 100644
--- a/content/browser/compositor/gpu_process_transport_factory.cc
+++ b/content/browser/compositor/gpu_process_transport_factory.cc
@@ -325,6 +325,15 @@ void GpuProcessTransportFactory::RemoveObserver(
   observer_list_.RemoveObserver(observer);
 }
 
+#if defined(OS_MACOSX)
+void GpuProcessTransportFactory::OnSurfaceDisplayed(int surface_id) {
+  BrowserCompositorOutputSurface* surface = output_surface_map_.Lookup(
+      surface_id);
+  if (surface)
+    surface->OnSurfaceDisplayed();
+}
+#endif
+
 scoped_refptr<cc::ContextProvider>
 GpuProcessTransportFactory::SharedMainThreadContextProvider() {
   if (shared_main_thread_contexts_.get())