Allow TransportController to create a QuicTransportChannel

webrtc/p2p/quic/quictransportchannel.h

Index: webrtc/p2p/quic/quictransportchannel.h
diff --git a/webrtc/p2p/quic/quictransportchannel.h b/webrtc/p2p/quic/quictransportchannel.h
index 430ed8d9c46ca2330c3fa0078f70f4470d2cccb1..e27df209e7ae0bfbf56d5cebce331ddd12e58c63 100644
--- a/webrtc/p2p/quic/quictransportchannel.h
+++ b/webrtc/p2p/quic/quictransportchannel.h
@@ -212,6 +212,8 @@ class QuicTransportChannel : public TransportChannelImpl,
   QuicTransportState quic_state() const { return quic_state_; }
   // Creates a new QUIC stream that can send data.
   ReliableQuicStream* CreateQuicStream();
+  // Needed by QuicTransport.
+  TransportChannelImpl* channel() const { return channel_; }
 
   // Emitted when |quic_| creates a QUIC stream to receive data from the remote
   // peer, when the stream did not exist previously.