Fix a breakage in chromoting due to an interface change.

webrtc/p2p/base/p2ptransportchannel.h

Index: webrtc/p2p/base/p2ptransportchannel.h
diff --git a/webrtc/p2p/base/p2ptransportchannel.h b/webrtc/p2p/base/p2ptransportchannel.h
index 96cb2be48c4eb8bdff5d895c361eac9dfe6bda7d..f6021615f083e19ea0684355e7c884a4a56eaea9 100644
--- a/webrtc/p2p/base/p2ptransportchannel.h
+++ b/webrtc/p2p/base/p2ptransportchannel.h
@@ -118,6 +118,10 @@ class P2PTransportChannel : public TransportChannelImpl,
   int GetError() override { return error_; }
   bool GetStats(std::vector<ConnectionInfo>* stats) override;
 
+  // TODO(honghaiz): Remove this method once the reference of it in
+  // Chromoting is removed.
+  const Connection* best_connection() const { return selected_connection_; }
+
   const Connection* selected_connection() const { return selected_connection_; }
   void set_incoming_only(bool value) { incoming_only_ = value; }