Cast: Add GetStats() extensions API.

chrome/renderer/extensions/cast_streaming_native_handler.h

Index: chrome/renderer/extensions/cast_streaming_native_handler.h
diff --git a/chrome/renderer/extensions/cast_streaming_native_handler.h b/chrome/renderer/extensions/cast_streaming_native_handler.h
index 52e1b97d1881948b52d284328811b3f92f506c3b..a7eb89fc39aaeb5a7a1ee2853b1b0546b67a2204 100644
--- a/chrome/renderer/extensions/cast_streaming_native_handler.h
+++ b/chrome/renderer/extensions/cast_streaming_native_handler.h
@@ -64,6 +64,7 @@ class CastStreamingNativeHandler : public ObjectBackedNativeHandler {
 
   void CallGetRawEventsCallback(int transport_id,
                                 scoped_ptr<std::string> raw_events);
+  void CallGetStatsCallback(int transport_id, scoped_ptr<std::string> stats);
 
   // Gets the RTP stream or UDP transport indexed by an ID.
   // If not found, returns NULL and throws a V8 exception.
@@ -86,6 +87,7 @@ class CastStreamingNativeHandler : public ObjectBackedNativeHandler {
                    linked_ptr<extensions::ScopedPersistent<v8::Function> > >
       RtpStreamCallbackMap;
   RtpStreamCallbackMap get_raw_events_callbacks_;
+  RtpStreamCallbackMap get_stats_callbacks_;
 
   DISALLOW_COPY_AND_ASSIGN(CastStreamingNativeHandler);
 };