RTCPeerConnection.addTrack and removeTrack added (behind flag)

content/shell/test_runner/mock_webrtc_peer_connection_handler.h

Index: content/shell/test_runner/mock_webrtc_peer_connection_handler.h
diff --git a/content/shell/test_runner/mock_webrtc_peer_connection_handler.h b/content/shell/test_runner/mock_webrtc_peer_connection_handler.h
index 415bee2108aac7942f663755287cdcb1fb11f040..1b76170933ebd151968f2f557f58304ceec066fb 100644
--- a/content/shell/test_runner/mock_webrtc_peer_connection_handler.h
+++ b/content/shell/test_runner/mock_webrtc_peer_connection_handler.h
@@ -65,6 +65,10 @@ class MockWebRTCPeerConnectionHandler
       override;
   blink::WebVector<std::unique_ptr<blink::WebRTCRtpReceiver>> GetReceivers()
       override;
+  std::unique_ptr<blink::WebRTCRtpSender> AddTrack(
+      const blink::WebMediaStreamTrack& web_track,
+      const blink::WebVector<blink::WebMediaStream>& web_streams) override;
+  bool RemoveTrack(blink::WebRTCRtpSender* web_sender) override;
   blink::WebRTCDataChannelHandler* CreateDataChannel(
       const blink::WebString& label,
       const blink::WebRTCDataChannelInit& init) override;
@@ -101,6 +105,8 @@ class MockWebRTCPeerConnectionHandler
   typedef std::map<std::string, blink::WebMediaStream> StreamMap;
   StreamMap local_streams_;
   StreamMap remote_streams_;
+  // Tracks added with |addTrack|, not including tracks of |local_streams_|.
+  std::map<std::string, blink::WebMediaStreamTrack> tracks_;
   std::map<std::string, uintptr_t> id_by_track_;
 
   base::WeakPtrFactory<MockWebRTCPeerConnectionHandler> weak_factory_;