Adding CastRemotingSender for media remoting.

chrome/renderer/media/cast_session.cc

Index: chrome/renderer/media/cast_session.cc
diff --git a/chrome/renderer/media/cast_session.cc b/chrome/renderer/media/cast_session.cc
index c9fc3a6b9e49effe9fb3d4c8c12567cfa78ea681..2f564c900d107b60934a7007bddb75f09d02893b 100644
--- a/chrome/renderer/media/cast_session.cc
+++ b/chrome/renderer/media/cast_session.cc
@@ -85,6 +85,18 @@ void CastSession::StartVideo(const media::cast::FrameSenderConfig& config,
                      base::Bind(&CreateVideoEncodeMemory))));
 }
 
+void CastSession::StartRemotingStream(
+    int32_t stream_id,
+    const media::cast::FrameSenderConfig& config,
+    const ErrorCallback& error_callback) {
+  DCHECK(content::RenderThread::Get());
+
+  io_task_runner_->PostTask(
+      FROM_HERE, base::Bind(&CastSessionDelegate::StartRemotingStream,
+                            base::Unretained(delegate_.get()), stream_id,

[dcheng, 2016/09/10 02:31:36]

How will this get cancelled if CastSession is destroyed?

[xjz, 2016/09/12 18:22:06]

It is always safe to post task on the IO thread to access CastSessionDelegate,
which is explained in the header file:
https://cs.chromium.org/chromium/src/chrome/renderer/media/cast_session.h?rcl...

+                            config, media::BindToCurrentLoop(error_callback)));
+}
+
 void CastSession::StartUDP(const net::IPEndPoint& remote_endpoint,
                            std::unique_ptr<base::DictionaryValue> options,
                            const ErrorCallback& error_callback) {