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

webrtc/p2p/base/fakepackettransport.h

Index: webrtc/p2p/base/fakepackettransport.h
diff --git a/webrtc/p2p/base/fakepackettransport.h b/webrtc/p2p/base/fakepackettransport.h
index 03966f9ca06c967029f57aaa4374a090eb97d028..7e2f08437ec9782164e70d1007e9fcc15d749117 100644
--- a/webrtc/p2p/base/fakepackettransport.h
+++ b/webrtc/p2p/base/fakepackettransport.h
@@ -13,6 +13,7 @@
 
 #include <string>
 
+#include "webrtc/api/ortc/packettransportinterface.h"
 #include "webrtc/base/asyncinvoker.h"
 #include "webrtc/base/copyonwritebuffer.h"
 #include "webrtc/p2p/base/packettransportinternal.h"
@@ -20,7 +21,8 @@
 namespace rtc {
 
 // Used to simulate a packet-based transport.
-class FakePacketTransport : public PacketTransportInternal {
+class FakePacketTransport : public PacketTransportInternal,
+                            public webrtc::PacketTransportInterface {
  public:
   explicit FakePacketTransport(const std::string& debug_name)
       : debug_name_(debug_name) {}
@@ -85,6 +87,9 @@ class FakePacketTransport : public PacketTransportInternal {
   bool GetOption(Socket::Option opt, int* value) override { return true; }
   int GetError() override { return 0; }
 
+ protected:
+  PacketTransportInternal* GetInternal() override { return this; }
+
  private:
   void set_writable(bool writable) {
     if (writable_ == writable) {