MediaStream audio: Refactor 3 separate "glue" implementations into one.

content/renderer/media/media_stream_source.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/renderer/media/media_stream_source.h"
 
 #include "base/callback_helpers.h"
 
 namespace content {
 
 const char MediaStreamSource::kSourceId[] = "sourceId";
 
 MediaStreamSource::MediaStreamSource() {
 }
 
-MediaStreamSource::~MediaStreamSource() {}
+MediaStreamSource::~MediaStreamSource() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  RunStopCallbackAndEndStream();
+}
 
 void MediaStreamSource::StopSource() {
+  DCHECK(thread_checker_.CalledOnValidThread());
   DoStopSource();
+  RunStopCallbackAndEndStream();
+}
+
+void MediaStreamSource::SetDeviceInfo(const StreamDeviceInfo& device_info) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  device_info_ = device_info;
+}
+
+void MediaStreamSource::SetStopCallback(
+    const SourceStoppedCallback& stop_callback) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  DCHECK(stop_callback_.is_null());
+  stop_callback_ = stop_callback;
+}
+
+void MediaStreamSource::ResetSourceStoppedCallback() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  DCHECK(!stop_callback_.is_null());
+  stop_callback_.Reset();
+}
+
+void MediaStreamSource::RunStopCallbackAndEndStream() {
+  DCHECK(thread_checker_.CalledOnValidThread());
   if (!stop_callback_.is_null())
     base::ResetAndReturn(&stop_callback_).Run(owner());
-
-  owner().setReadyState(blink::WebMediaStreamSource::ReadyStateEnded);
+  if (!owner().isNull())
+    owner().setReadyState(blink::WebMediaStreamSource::ReadyStateEnded);
 }
 
 }  // namespace content