Remove event_channel() and control_channel() from Session interface.

remoting/protocol/rtp_video_writer.cc

Index: remoting/protocol/rtp_video_writer.cc
diff --git a/remoting/protocol/rtp_video_writer.cc b/remoting/protocol/rtp_video_writer.cc
index 7d83d06fe72eac34ed4d31e644faa998fff2aee4..5c924870518d187e552a6b70de10a8fa6abdcd87 100644
--- a/remoting/protocol/rtp_video_writer.cc
+++ b/remoting/protocol/rtp_video_writer.cc
@@ -44,6 +44,10 @@ void RtpVideoWriter::Init(protocol::Session* session,
                  base::Unretained(this), false));
 }
 
+bool RtpVideoWriter::is_connected() {
+  return rtp_channel_.get() && rtcp_channel_.get();
+}
+
 void RtpVideoWriter::OnChannelReady(bool rtp, net::Socket* socket) {
   if (!socket) {
     if (!initialized_) {