Adding "adapter" ORTC objects on top of ChannelManager/BaseChannel/etc.

webrtc/api/ortc/packettransportinterface.h

Index: webrtc/api/ortc/packettransportinterface.h
diff --git a/webrtc/api/ortc/packettransportinterface.h b/webrtc/api/ortc/packettransportinterface.h
new file mode 100644
index 0000000000000000000000000000000000000000..2677ce62ca3b22208740c51c53858a2ff141ddf2
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+++ b/webrtc/api/ortc/packettransportinterface.h
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+/*
+ *  Copyright 2017 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef WEBRTC_API_ORTC_PACKETTRANSPORTINTERFACE_H_
+#define WEBRTC_API_ORTC_PACKETTRANSPORTINTERFACE_H_
+
+namespace rtc {
+
+class PacketTransportInternal;
+
+}  // namespace rtc
+
+namespace webrtc {
+
+// Base class for different packet-based transports.
+class PacketTransportInterface {
+ public:
+  virtual ~PacketTransportInterface() {}
+
+ protected:
+  // Only for internal use. Returns a pointer to an internal interface, for use
+  // by the implementation.
+  virtual rtc::PacketTransportInternal* GetInternal() = 0;
+
+  // Classes that can use this internal interface.
+  friend class RtpTransportControllerAdapter;
+};
+
+}  // namespace webrtc
+
+#endif  // WEBRTC_API_ORTC_PACKETTRANSPORTINTERFACE_H_