Collect all ConnectionAttempts from both sockets in TransportConnectJob.

remoting/protocol/channel_multiplexer.cc

Index: remoting/protocol/channel_multiplexer.cc
diff --git a/remoting/protocol/channel_multiplexer.cc b/remoting/protocol/channel_multiplexer.cc
index 832fba39894897d5cb4917095d77cef2526df258..8cdbf0d60af091469c6acb327211529f2e8f2444 100644
--- a/remoting/protocol/channel_multiplexer.cc
+++ b/remoting/protocol/channel_multiplexer.cc
@@ -165,6 +165,12 @@ class ChannelMultiplexer::MuxSocket : public net::StreamSocket,
     NOTIMPLEMENTED();
     return false;
   }
+  void GetConnectionAttempts(net::ConnectionAttempts* out) const override {
+    out->clear();
+  }
+  void ClearConnectionAttempts() override {}
+  void AddConnectionAttempts(const net::ConnectionAttempts& attempts) override {
+  }
 
  private:
   MuxChannel* channel_;