Add back P2PTransportChannel.Connect, for Chromium.

Will remove it as soon as Chromium does a roll and can stop using it.

TBR=pthatcher@webrtc.org
NOTRY=True

Review-Url: https://codereview.webrtc.org/2110853005
Cr-Commit-Position: refs/heads/master@{#13332}

webrtc/p2p/base/p2ptransportchannel.h

@@ -93,6 +93,9 @@ class P2PTransportChannel : public TransportChannelImpl,
   void SetRemoteIceCredentials(const std::string& ice_ufrag,
                                const std::string& ice_pwd) override;
   void SetRemoteIceMode(IceMode mode) override;
+  // TODO(deadbeef): Deprecated. Remove when Chromium's
+  // IceTransportChannel does not depend on this.
+  void Connect() {}
   void MaybeStartGathering() override;
   IceGatheringState gathering_state() const override {
     return gathering_state_;