[Remoting Host] Supporting WebRTC VP9 streaming

remoting/protocol/webrtc_transport.cc

Index: remoting/protocol/webrtc_transport.cc
diff --git a/remoting/protocol/webrtc_transport.cc b/remoting/protocol/webrtc_transport.cc
index 693521c382bfca0ed2257de473743103d62eaaa0..1b40c6cd76ac3c552b8479bcbef6ca82d6a355bb 100644
--- a/remoting/protocol/webrtc_transport.cc
+++ b/remoting/protocol/webrtc_transport.cc
@@ -80,6 +80,15 @@ void UpdateCodecParameters(SdpMessage* sdp_message, bool incoming) {
       LOG(FATAL) << "VP8 not found in SDP generated by WebRTC.";
     }
   }
+  if (sdp_message->has_video() &&
+      !sdp_message->AddCodecParameter(
+          "VP9", "x-google-min-bitrate=1000; x-google-max-bitrate=100000")) {
+    if (incoming) {
+      LOG(WARNING) << "VP9 not found in an incoming SDP.";

[Sergey Ulanov, 2017/03/31 19:23:11]

I think we should log this message only of neither VP8 nor VP9 is found. I.e.
the client should be allowed to remove VP8 or VP9.

[Yuwei, 2017/04/03 22:29:10]

Done.

+    } else {
+      LOG(FATAL) << "VP9 not found in SDP generated by WebRTC.";
+    }
+  }
 
   // Update SDP format to use 160kbps stereo for opus codec.
   if (sdp_message->has_audio() &&