Interface RTCRtpReceiver and RTCPeerConnection.getReceivers() added.

content/renderer/media/rtc_peer_connection_handler.h

Index: content/renderer/media/rtc_peer_connection_handler.h
diff --git a/content/renderer/media/rtc_peer_connection_handler.h b/content/renderer/media/rtc_peer_connection_handler.h
index 0b1d64f934e80eb1dd2bcf75fbfc84cfbc625eec..65c17b2aa49cf0d39bd18f63143829782fc1eadd 100644
--- a/content/renderer/media/rtc_peer_connection_handler.h
+++ b/content/renderer/media/rtc_peer_connection_handler.h
@@ -147,6 +147,8 @@ class CONTENT_EXPORT RTCPeerConnectionHandler
   void getStats(const blink::WebRTCStatsRequest& request) override;
   void getStats(
       std::unique_ptr<blink::WebRTCStatsReportCallback> callback) override;
+  blink::WebVector<std::unique_ptr<blink::WebRTCRtpReceiver>> getReceivers()
+      override;
   blink::WebRTCDataChannelHandler* createDataChannel(
       const blink::WebString& label,
       const blink::WebRTCDataChannelInit& init) override;
@@ -233,6 +235,13 @@ class CONTENT_EXPORT RTCPeerConnectionHandler
   void RunSynchronousClosureOnSignalingThread(const base::Closure& closure,
                                               const char* trace_event_name);
 
+  // If a track is not found with the specified id, the returned track's
+  // |isNull| will return true.
+  blink::WebMediaStreamTrack GetRemoteAudioTrack(
+      const std::string& track_id) const;
+  blink::WebMediaStreamTrack GetRemoteVideoTrack(
+      const std::string& track_id) const;
+
   base::ThreadChecker thread_checker_;
 
   // |client_| is a weak pointer to the blink object (blink::RTCPeerConnection)