Adds MediaStreamSource, MediaStreamAudioSource and MediaStreamVideoCaptureDeviceSource

content/renderer/media/media_stream_source.h

+// 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.
+
+#ifndef CONTENT_RENDERER_MEDIA_MEDIA_STREAM_SOURCE_H_
+#define CONTENT_RENDERER_MEDIA_MEDIA_STREAM_SOURCE_H_
+
+#include "base/callback.h"
+#include "base/compiler_specific.h"
+#include "content/common/content_export.h"
+#include "content/common/media/media_stream_options.h"
+#include "third_party/WebKit/public/platform/WebMediaStreamSource.h"
+
+namespace blink {
+class WebMediaStreamTrack;
+}  // namespace blink
+
+namespace content {
+
+class CONTENT_EXPORT MediaStreamSource
+    : NON_EXPORTED_BASE(public blink::WebMediaStreamSource::ExtraData) {
+ public:
+  typedef base::Callback<void(const blink::WebMediaStreamSource& source)>
+      SourceStoppedCallback;
+
+  typedef base::Callback<void(MediaStreamSource* source,
+                              bool success)> ConstraintsCallback;
+
+  MediaStreamSource();
+  virtual ~MediaStreamSource();
+
+  virtual void AddTrack(const blink::WebMediaStreamTrack& track,
+                        const blink::WebMediaConstraints& constraints,
+                        const ConstraintsCallback& callback) = 0;
+  virtual void RemoveTrack(const blink::WebMediaStreamTrack& track) = 0;
+
+  // Return device information about the camera or microphone.

[Ronghua Wu (Left Chromium), 2014/01/16 23:02:37]

camera or microphone should just be 2 examples. suggest to update the comment
accordingly.

[perkj_chrome, 2014/01/17 13:19:45]

ok.
This method isn't something I am very proud of. It only applies for those types
of sources that comes from GetUserMedia.

+  const StreamDeviceInfo& device_info() const {
+    return device_info_;
+  }
+
+  // Stops the source (by calling DoStopSource()). This sets the
+  // WebMediaStreamSource::readyState to ended, triggers the |stop_callback_|
+  // if set. All pointers to this object is invalid after calling this.

[Jói, 2014/01/17 08:57:08]

nit: is invalid -> are invalid

[perkj_chrome, 2014/01/17 13:19:45]

Done.

+  void StopSource();
+
+  void ResetSourceStoppedCallback() {
+    DCHECK(!stop_callback_.is_null());
+    stop_callback_.Reset();
+  }
+
+ protected:
+  // Called when OnLocalsSource is called.

[Ronghua Wu (Left Chromium), 2014/01/16 23:02:37]

comment is confusing to me

[perkj_chrome, 2014/01/17 13:19:45]

Since its wrong after I renamed the method maybe? 

+  virtual void DoStopSource() = 0;
+
+  // Set device information about the camera or microphone.

[Ronghua Wu (Left Chromium), 2014/01/16 23:02:37]

camera or microphone should just be 2 examples. suggest to update the comment
accordingly.

[perkj_chrome, 2014/01/17 13:19:45]

Done.

+  void SetDeviceInfo(const StreamDeviceInfo& device_info) {
+    device_info_ = device_info;
+  }
+
+  // Set a callback that is triggered when OnLocalSourceStop is called.

[Ronghua Wu (Left Chromium), 2014/01/16 23:02:37]

"will be triggered"?

[perkj_chrome, 2014/01/17 13:19:45]

Done.

+  void SetStopCallback(const SourceStoppedCallback& stop_callback) {
+    DCHECK(stop_callback_.is_null());
+    stop_callback_ = stop_callback;
+  }
+
+ private:
+  StreamDeviceInfo device_info_;
+

[Ronghua Wu (Left Chromium), 2014/01/16 23:02:37]

remove empty line

[perkj_chrome, 2014/01/17 13:19:45]

Done.

+  SourceStoppedCallback stop_callback_;
+
+  DISALLOW_COPY_AND_ASSIGN(MediaStreamSource);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_RENDERER_MEDIA_MEDIA_STREAM_SOURCE_H_