Add client and host dispatchers for video_stats channel to send video stats from host to client.

remoting/protocol/frame_stats.h

Index: remoting/protocol/frame_stats.h
diff --git a/remoting/protocol/frame_stats.h b/remoting/protocol/frame_stats.h
index c2c5ad9d2a743c9566f68524ef0178e47ec0cf3b..7727b712d7717996970556e1b95c2d81a664a306 100644
--- a/remoting/protocol/frame_stats.h
+++ b/remoting/protocol/frame_stats.h
@@ -22,6 +22,10 @@ struct HostFrameStats {
   // Extracts timing fields from the |packet|.
   static HostFrameStats GetForVideoPacket(const VideoPacket& packet);
 
+  // Converts FrameStatsMessage protobuf message to HostFrameStats.
+  static HostFrameStats FromFrameStatsMessage(const FrameStatsMessage& message);
+  void ToFrameStatsMessage(FrameStatsMessage* message_out) const;
+
   // Frame Size.
   int frame_size {};