Implement aura::WindowPortMus::CreateCompositorFrameSink()

components/viz/client/client_compositor_frame_sink.h

Index: components/viz/client/client_compositor_frame_sink.h
diff --git a/components/viz/client/client_compositor_frame_sink.h b/components/viz/client/client_compositor_frame_sink.h
index 008b730264ab968aed9caee42e69c5f329b49078..f86e316295ce19aeaab08436ce74ead400b914a7 100644
--- a/components/viz/client/client_compositor_frame_sink.h
+++ b/components/viz/client/client_compositor_frame_sink.h
@@ -6,6 +6,7 @@
 #define COMPONENTS_VIZ_CLIENT_CLIENT_COMPOSITOR_FRAME_SINK_H_
 
 #include "base/macros.h"
+#include "base/memory/weak_ptr.h"
 #include "cc/ipc/mojo_compositor_frame_sink.mojom.h"
 #include "cc/output/compositor_frame_sink.h"
 #include "cc/output/context_provider.h"
@@ -42,6 +43,8 @@ class ClientCompositorFrameSink
 
   ~ClientCompositorFrameSink() override;
 
+  base::WeakPtr<ClientCompositorFrameSink> GetWeakPtr();
+
   // cc::CompositorFrameSink implementation.
   bool BindToClient(cc::CompositorFrameSinkClient* client) override;
   void DetachFromClient() override;
@@ -76,6 +79,8 @@ class ClientCompositorFrameSink
   THREAD_CHECKER(thread_checker_);
   const bool enable_surface_synchronization_;
 
+  base::WeakPtrFactory<ClientCompositorFrameSink> weak_factory_;
+
   DISALLOW_COPY_AND_ASSIGN(ClientCompositorFrameSink);
 };