Revert of Remove GetTransport() from TransportChannelImpl

webrtc/p2p/base/dtlstransportchannel.h

Index: webrtc/p2p/base/dtlstransportchannel.h
diff --git a/webrtc/p2p/base/dtlstransportchannel.h b/webrtc/p2p/base/dtlstransportchannel.h
index f396a57d30ede0a5b9ab4042751459400d7aaa4d..955b963a3657a1efc7436e4347158b02e7e112e2 100644
--- a/webrtc/p2p/base/dtlstransportchannel.h
+++ b/webrtc/p2p/base/dtlstransportchannel.h
@@ -82,8 +82,10 @@
 class DtlsTransportChannelWrapper : public TransportChannelImpl {
  public:
   // The parameters here are:
+  // transport -- the DtlsTransport that created us
   // channel -- the TransportChannel we are wrapping
-  explicit DtlsTransportChannelWrapper(TransportChannelImpl* channel);
+  DtlsTransportChannelWrapper(Transport* transport,
+                              TransportChannelImpl* channel);
   ~DtlsTransportChannelWrapper() override;
 
   void SetIceRole(IceRole role) override { channel_->SetIceRole(role); }
@@ -157,6 +159,8 @@
   }
 
   // TransportChannelImpl calls.
+  Transport* GetTransport() override { return transport_; }
+
   TransportChannelState GetState() const override {
     return channel_->GetState();
   }
@@ -214,8 +218,9 @@
   void OnConnectionRemoved(TransportChannelImpl* channel);
   void Reconnect();
 
+  Transport* transport_;  // The transport_ that created us.
   rtc::Thread* worker_thread_;  // Everything should occur on this thread.
-  // Underlying channel, not owned by this class.
+  // Underlying channel, owned by transport_.
   TransportChannelImpl* const channel_;
   rtc::scoped_ptr<rtc::SSLStreamAdapter> dtls_;  // The DTLS stream
   StreamInterfaceChannel* downward_;  // Wrapper for channel_, owned by dtls_.