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

webrtc/config.cc

Index: webrtc/config.cc
diff --git a/webrtc/config.cc b/webrtc/config.cc
index 6ffd1c3fd1563f2d50dd0462c0117b61ea591f3e..e0c490d1ecd8038d546b7298fc9a885ab02718df 100644
--- a/webrtc/config.cc
+++ b/webrtc/config.cc
@@ -72,6 +72,9 @@ const char* RtpExtension::kPlayoutDelayUri =
     "http://www.webrtc.org/experiments/rtp-hdrext/playout-delay";
 const int RtpExtension::kPlayoutDelayDefaultId = 6;
 
+const int RtpExtension::kMinId = 1;
+const int RtpExtension::kMaxId = 14;
+
 bool RtpExtension::IsSupportedForAudio(const std::string& uri) {
   return uri == webrtc::RtpExtension::kAudioLevelUri ||
          uri == webrtc::RtpExtension::kTransportSequenceNumberUri;