MediaRecorder: make MediaRecorderHandler a MediaStreamObserver

content/renderer/media/media_recorder_handler.h

 // Copyright 2015 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_RECORDER_HANDLER_H_
 #define CONTENT_RENDERER_MEDIA_MEDIA_RECORDER_HANDLER_H_
 
 #include "base/compiler_specific.h"
 #include "base/memory/scoped_vector.h"
 #include "base/memory/weak_ptr.h"
 #include "base/strings/string_piece.h"
 #include "base/threading/thread_checker.h"
 #include "content/common/content_export.h"
+#include "content/renderer/media/media_stream.h"
 #include "third_party/WebKit/public/platform/WebMediaRecorderHandler.h"
 #include "third_party/WebKit/public/platform/WebMediaStream.h"
 
 namespace blink {
 class WebMediaRecorderHandlerClient;
 class WebString;
 }  // namespace blink
 
 namespace media {
 class AudioBus;
@@ skipping 10 matching lines @@
 // MediaRecorderHandler orchestrates the creation, lifetime management and
 // mapping between:
 // - MediaStreamTrack(s) providing data,
 // - {Audio,Video}TrackRecorders encoding that data,
 // - a WebmMuxer class multiplexing encoded data into a WebM container, and
 // - a single recorder client receiving this contained data.
 // All methods are called on the same thread as construction and destruction,
 // i.e. the Main Render thread. (Note that a BindToCurrentLoop is used to
 // guarantee this, since VideoTrackRecorder sends back frames on IO thread.)
 class CONTENT_EXPORT MediaRecorderHandler final
-    : public NON_EXPORTED_BASE(blink::WebMediaRecorderHandler) {
+    : public NON_EXPORTED_BASE(blink::WebMediaRecorderHandler),
+      public NON_EXPORTED_BASE(MediaStreamObserver) {
  public:
   MediaRecorderHandler();
   ~MediaRecorderHandler() override;
 
   // blink::WebMediaRecorderHandler.
   bool canSupportMimeType(const blink::WebString& web_type,
                           const blink::WebString& web_codecs) override;
   bool initialize(blink::WebMediaRecorderHandlerClient* client,
                   const blink::WebMediaStream& media_stream,
                   const blink::WebString& type,
                   const blink::WebString& codecs) override;
   bool start() override;
   bool start(int timeslice) override;
   void stop() override;
   void pause() override;
   void resume() override;
 
+  // MediaStreamObserver implementation. On MS modification, we stop recording
+  // and signal this illegal condition to |client_|.
+  void TrackAdded(const blink::WebMediaStreamTrack& track) override;
+  void TrackRemoved(const blink::WebMediaStreamTrack& track) override;
+
  private:
   friend class MediaRecorderHandlerTest;
 
   void OnEncodedVideo(const scoped_refptr<media::VideoFrame>& video_frame,
                       scoped_ptr<std::string> encoded_data,
                       base::TimeTicks timestamp,
                       bool is_key_frame);
   void OnEncodedAudio(const media::AudioParameters& params,
                       scoped_ptr<std::string> encoded_data,
                       base::TimeTicks timestamp);
@@ skipping 29 matching lines @@
   // Worker class doing the actual Webm Muxing work.
   scoped_ptr<media::WebmMuxer> webm_muxer_;
 
   base::WeakPtrFactory<MediaRecorderHandler> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(MediaRecorderHandler);
 };
 
 }  // namespace content
 #endif  // CONTENT_RENDERER_MEDIA_MEDIA_RECORDER_HANDLER_H_