Add observers to FrameSinkManagerHost.

content/browser/compositor/frame_sink_manager_host.cc

Index: content/browser/compositor/frame_sink_manager_host.cc
diff --git a/content/browser/compositor/frame_sink_manager_host.cc b/content/browser/compositor/frame_sink_manager_host.cc
index 089abdb261b76fd90b8d288092330150d88ff8ff..3ffc3d7f5455c6c423c387c9cf57875b5d434750 100644
--- a/content/browser/compositor/frame_sink_manager_host.cc
+++ b/content/browser/compositor/frame_sink_manager_host.cc
@@ -24,6 +24,14 @@ cc::SurfaceManager* FrameSinkManagerHost::surface_manager() {
   return frame_sink_manager_.surface_manager();
 }
 
+void FrameSinkManagerHost::AddObserver(cc::SurfaceObserver* observer) {
+  observers_.AddObserver(observer);
+}
+
+void FrameSinkManagerHost::RemoveObserver(cc::SurfaceObserver* observer) {
+  observers_.RemoveObserver(observer);
+}
+
 void FrameSinkManagerHost::CreateCompositorFrameSink(
     const cc::FrameSinkId& frame_sink_id,
     cc::mojom::MojoCompositorFrameSinkRequest request,
@@ -50,7 +58,8 @@ void FrameSinkManagerHost::UnregisterFrameSinkHierarchy(
 
 void FrameSinkManagerHost::OnSurfaceCreated(
     const cc::SurfaceInfo& surface_info) {
-  // TODO(kylechar): Implement.
+  for (auto& observer : observers_)
+    observer.OnSurfaceCreated(surface_info);
 }
 
 }  // namespace content