Convert mustash use surface references.

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 18ad01a7ff3a613e08a28f35f8e0443b913701c5..aaeea1e743f76336eb2ab05bdfd2976f45e9b421 100644
--- a/services/ui/surfaces/display_compositor.h
+++ b/services/ui/surfaces/display_compositor.h
@@ -10,6 +10,7 @@
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "cc/ipc/display_compositor.mojom.h"
+#include "cc/surfaces/frame_sink_id.h"
 #include "cc/surfaces/surface_manager.h"
 #include "cc/surfaces/surface_observer.h"
 
@@ -33,10 +34,10 @@ class DisplayCompositor : public cc::SurfaceObserver,
   explicit DisplayCompositor(cc::mojom::DisplayCompositorClientPtr client);
 
   // TODO(fsamuel):  These methods should be behind a mojo interface.
-  void AddSurfaceReference(const cc::SurfaceId& surface_id,
-                           const cc::SurfaceSequence& surface_sequence);
-  void ReturnSurfaceReferences(const cc::FrameSinkId& frame_sink_id,
-                               const std::vector<uint32_t>& sequences);
+  void AddSurfaceReference(const cc::SurfaceId& parent_id,
+                           const cc::SurfaceId& child_id);
+  void RemoveSurfaceReference(const cc::SurfaceId& parent_id,
+                              const cc::SurfaceId& child_id);
 
   cc::SurfaceManager* manager() { return &manager_; }
 
@@ -54,6 +55,15 @@ class DisplayCompositor : public cc::SurfaceObserver,
   cc::mojom::DisplayCompositorClientPtr client_;
   cc::SurfaceManager manager_;
 
+  // TODO(fsamuel): Comment on this CL and let me know what ??? below should be,
+  // DisplayCompositorHost or has the name changed?
+  // SurfaceIds that have temporary references from |kRootSurfaceId| so they
+  // aren't GC'd before ??? can add a real reference.
+  std::unordered_map<cc::FrameSinkId,
+                     std::vector<cc::LocalFrameId>,
+                     cc::FrameSinkIdHash>
+      temp_references_;
+
   DISALLOW_COPY_AND_ASSIGN(DisplayCompositor);
 };