Implement MediaSession on top of the WebMediaPlayerDelegate.

content/renderer/media/webmediaplayer_ms.h

 // Copyright 2013 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_WEBMEDIAPLAYER_MS_H_
 #define CONTENT_RENDERER_MEDIA_WEBMEDIAPLAYER_MS_H_
 
 #include <string>
 
 #include "base/macros.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
 #include "base/synchronization/lock.h"
 #include "base/threading/thread_checker.h"
 #include "content/common/content_export.h"
-#include "content/public/renderer/render_frame_observer.h"
+#include "media/blink/webmediaplayer_delegate.h"
 #include "media/blink/webmediaplayer_util.h"
 #include "media/renderers/gpu_video_accelerator_factories.h"
 #include "media/renderers/skcanvas_video_renderer.h"
 #include "third_party/WebKit/public/platform/WebMediaPlayer.h"
 #include "url/origin.h"
 
 namespace blink {
 class WebFrame;
 class WebGraphicsContext3D;
 class WebMediaPlayerClient;
 class WebSecurityOrigin;
 class WebString;
 }
 
 namespace media {
 class MediaLog;
-class WebMediaPlayerDelegate;
 class VideoFrame;
 }
 
 namespace cc_blink {
 class WebLayerImpl;
 }
 
 namespace content {
 class MediaStreamAudioRenderer;
 class MediaStreamRendererFactory;
 class VideoFrameProvider;
 class WebMediaPlayerMSCompositor;
 class RenderFrameObserver;
 
 // WebMediaPlayerMS delegates calls from WebCore::MediaPlayerPrivate to
 // Chrome's media player when "src" is from media stream.
 //
 // All calls to WebMediaPlayerMS methods must be from the main thread of
 // Renderer process.
 //
 // WebMediaPlayerMS works with multiple objects, the most important ones are:
 //
 // VideoFrameProvider
 //   provides video frames for rendering.
 //
 // blink::WebMediaPlayerClient
 //   WebKit client of this media player object.
 class CONTENT_EXPORT WebMediaPlayerMS
     : public NON_EXPORTED_BASE(blink::WebMediaPlayer),
-      public NON_EXPORTED_BASE(base::SupportsWeakPtr<WebMediaPlayerMS>),
-      public NON_EXPORTED_BASE(RenderFrameObserver) {
+      public NON_EXPORTED_BASE(media::WebMediaPlayerDelegate::Observer),
+      public NON_EXPORTED_BASE(base::SupportsWeakPtr<WebMediaPlayerMS>) {
  public:
   // Construct a WebMediaPlayerMS with reference to the client, and
   // a MediaStreamClient which provides VideoFrameProvider.
   WebMediaPlayerMS(
       blink::WebFrame* frame,
       blink::WebMediaPlayerClient* client,
       base::WeakPtr<media::WebMediaPlayerDelegate> delegate,
       media::MediaLog* media_log,
       scoped_ptr<MediaStreamRendererFactory> factory,
       const scoped_refptr<base::SingleThreadTaskRunner>& compositor_task_runner,
@@ skipping 53 matching lines @@
   bool hasSingleSecurityOrigin() const override;
   bool didPassCORSAccessCheck() const override;
 
   double mediaTimeForTimeValue(double timeValue) const override;
 
   unsigned decodedFrameCount() const override;
   unsigned droppedFrameCount() const override;
   unsigned audioDecodedByteCount() const override;
   unsigned videoDecodedByteCount() const override;
 
-  // RenderFrameObserver implementation. Called when the RenderFrame visiblity
-  // is changed.
-  void WasHidden() override;
-  void WasShown() override;
+  // WebMediaPlayerDelegate::Observer implementation.
+  void OnHidden() override;
+  void OnShown() override;
+  void OnPlay() override;
+  void OnPause() override;
+  void OnVolumeMultiplierUpdate(double multiplier) override;
 
   bool copyVideoTextureToPlatformTexture(
       blink::WebGraphicsContext3D* web_graphics_context,
       unsigned int texture,
       unsigned int internal_format,
       unsigned int type,
       bool premultiply_alpha,
       bool flip_y) override;
 
  private:
@@ skipping 17 matching lines @@
 
   blink::WebFrame* const frame_;
 
   blink::WebMediaPlayer::NetworkState network_state_;
   blink::WebMediaPlayer::ReadyState ready_state_;
 
   const blink::WebTimeRanges buffered_;
 
   blink::WebMediaPlayerClient* const client_;
 
+  // WebMediaPlayer notifies the |delegate_| of playback state changes using
+  // |delegate_id_|; an id provided after registering with the delegate.  The
+  // WebMediaPlayer may also receive directives (play, pause) from the delegate
+  // via the WebMediaPlayerDelegate::Observer interface after registration.
   const base::WeakPtr<media::WebMediaPlayerDelegate> delegate_;
+  int delegate_id_;
 
   // Specify content:: to disambiguate from cc::.
   scoped_refptr<content::VideoFrameProvider> video_frame_provider_;  // Weak
 
   scoped_ptr<cc_blink::WebLayerImpl> video_weblayer_;
 
   scoped_refptr<MediaStreamAudioRenderer> audio_renderer_;  // Weak
   media::SkCanvasVideoRenderer video_renderer_;
 
   bool paused_;
@@ skipping 13 matching lines @@
 
   // WebMediaPlayerMS owns |compositor_| and destroys it on
   // |compositor_task_runner_|.
   scoped_ptr<WebMediaPlayerMSCompositor> compositor_;
 
   const scoped_refptr<base::SingleThreadTaskRunner> compositor_task_runner_;
 
   const std::string initial_audio_output_device_id_;
   const url::Origin initial_security_origin_;
 
+  // The last volume received by setVolume() and the last volume multiplier from
+  // OnVolumeMultiplierUpdate().  The multiplier is typical 1.0, but may be less
+  // if the WebMediaPlayerDelegate has requested a volume reduction (ducking)
+  // for a transient sound.  Playout volume is derived by volume * multiplier.
+  double volume_;
+  double volume_multiplier_;
+
   DISALLOW_COPY_AND_ASSIGN(WebMediaPlayerMS);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_MEDIA_WEBMEDIAPLAYER_MS_H_