Modified PeerConnection and WebRtcSession for end-to-end QuicDataChannel usage.

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 1ab13fa0b217118a04ea00032ea168d1533012a0..eec82be73f3b2758cc93e4cbcd4357e6815d6655 100644
--- a/webrtc/p2p/quic/quictransportchannel.h
+++ b/webrtc/p2p/quic/quictransportchannel.h
@@ -211,6 +211,8 @@ class QuicTransportChannel : public TransportChannelImpl,
   // Creates a new QUIC stream that can send data.
   ReliableQuicStream* CreateQuicStream();
 
+  TransportChannelImpl* ice_transport_channel() { return channel_.get(); }
+
   // Emitted when |quic_| creates a QUIC stream to receive data from the remote
   // peer, when the stream did not exist previously.
   sigslot::signal1<ReliableQuicStream*> SignalIncomingStream;