cc: Plumbing for BeginFrameSource based on Surfaces

cc/surfaces/surface.h

Index: cc/surfaces/surface.h
diff --git a/cc/surfaces/surface.h b/cc/surfaces/surface.h
index 8ef332ecb79756735b8f6760d23b34d954d973cd..18ca7442af6b4cd74a5a0d47e6a89b5be4af426b 100644
--- a/cc/surfaces/surface.h
+++ b/cc/surfaces/surface.h
@@ -6,6 +6,7 @@
 #define CC_SURFACES_SURFACE_H_
 
 #include <map>
+#include <set>
 #include <vector>
 
 #include "base/callback.h"
@@ -80,8 +81,12 @@ class CC_SURFACES_EXPORT Surface {
   bool destroyed() const { return destroyed_; }
   void set_destroyed(bool destroyed) { destroyed_ = destroyed; }
 
+  void AddBeginFrameSource(BeginFrameSource* begin_frame_source);
+  void RemoveBeginFrameSource(BeginFrameSource* begin_frame_source);
+
  private:
   void ClearCopyRequests();
+  void UpdatePrimaryBeginFrameSource();
 
   SurfaceId surface_id_;
   base::WeakPtr<SurfaceFactory> factory_;
@@ -91,6 +96,10 @@ class CC_SURFACES_EXPORT Surface {
   bool destroyed_;
   std::vector<SurfaceSequence> destruction_dependencies_;
 
+  // This surface may have multiple BeginFrameSources if it is
+  // on multiple Displays.
+  std::set<BeginFrameSource*> begin_frame_sources_;
+
   std::vector<SurfaceId> referenced_surfaces_;
 
   DrawCallback draw_callback_;