Decouple GpuCompositorFrameSink from DisplayCompositor

services/ui/surfaces/display_compositor.h

Index: services/ui/surfaces/display_compositor.h
diff --git a/services/ui/surfaces/display_compositor.h b/services/ui/surfaces/display_compositor.h
index 8616b1e40d08a057c4ac83a0752826fd064ea342..bb5a91c87d89ce3351296af6bb0c9b47884e7d55 100644
--- a/services/ui/surfaces/display_compositor.h
+++ b/services/ui/surfaces/display_compositor.h
@@ -14,6 +14,7 @@
 #include "base/macros.h"
 #include "base/threading/thread_checker.h"
 #include "cc/ipc/display_compositor.mojom.h"
+#include "cc/surfaces/compositor_frame_sink_delegate.h"
 #include "cc/surfaces/frame_sink_id.h"
 #include "cc/surfaces/local_frame_id.h"
 #include "cc/surfaces/surface_id.h"
@@ -46,6 +47,7 @@ class GpuCompositorFrameSink;
 // TODO(rjkroege, fsamuel): This object will need to change to support multiple
 // displays.
 class DisplayCompositor : public cc::SurfaceObserver,
+                          public cc::CompositorFrameSinkDelegate,
                           public cc::mojom::DisplayCompositor {
  public:
   DisplayCompositor(
@@ -58,24 +60,13 @@ class DisplayCompositor : public cc::SurfaceObserver,
 
   cc::SurfaceManager* manager() { return &manager_; }
 
-  // Adds surface references. For each reference added, this will remove the
-  // temporary reference to the child surface if one exists.
-  void AddSurfaceReferences(
-      const std::vector<cc::SurfaceReference>& references);
-
-  // Removes surface references.
-  void RemoveSurfaceReferences(
-      const std::vector<cc::SurfaceReference>& references);
-
   // We must avoid destroying a GpuCompositorFrameSink until both the display
   // compositor host and the client drop their connection to avoid getting into
   // a state where surfaces references are inconsistent.
-  void OnCompositorFrameSinkClientConnectionLost(
-      const cc::FrameSinkId& frame_sink_id,
-      bool destroy_compositor_frame_sink);
-  void OnCompositorFrameSinkPrivateConnectionLost(
-      const cc::FrameSinkId& frame_sink_id,
-      bool destroy_compositor_frame_sink);
+  void OnClientConnectionLost(const cc::FrameSinkId& frame_sink_id,
+                              bool destroy_compositor_frame_sink) override;
+  void OnPrivateConnectionLost(const cc::FrameSinkId& frame_sink_id,
+                               bool destroy_compositor_frame_sink) override;
 
   // cc::mojom::DisplayCompositor implementation:
   void CreateDisplayCompositorFrameSink(