WIP - WebMediaPlayer switch media renderer.

media/base/mediaplayer_observer.h

+// Copyright 2016 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 MEDIA_BASE_MEDIAPLAYER_OBSERVER_H_
+#define MEDIA_BASE_MEDIAPLAYER_OBSERVER_H_
+
+#include "base/callback.h"
+#include "media/base/audio_decoder_config.h"
+#include "media/base/cdm_context.h"
+#include "media/base/video_decoder_config.h"
+
+namespace media {
+
+// This class is an observer of a media player and can trigger a pipeline
+// restart (suspend/resume) to switch renderer if the callback is set.
+class MediaPlayerObserver {
+ public:
+  MediaPlayerObserver();
+  virtual ~MediaPlayerObserver();
+
+  // Called when the media element or its ancestor is entered/exited fullscreen.
+  virtual void OnEnteredFullscreen() = 0;
+  virtual void OnExitedFullscreen() = 0;
+
+  // Called when CDM is attached to a media element.
+  virtual void OnSetCdm(CdmContext* cdm_context) = 0;
+
+  // Set video/audio config after demuxer is initialized.
+  virtual void OnDecoderConfigChanged(
+      const AudioDecoderConfig& audio_config,
+      const VideoDecoderConfig& video_config) = 0;
+
+  // Set the callback to schedule restart of pipeline to switch renderer.
+  using SwitchRendererCallback = base::Callback<void()>;
+  virtual void SetSwitchRenderCallback(const SwitchRendererCallback& cb) = 0;

[miu, 2016/09/30 08:12:10]

Hmm...Everything except this looks like an "observed event of interest." Is
there a simple way to not have this method in this observer interface? Maybe
this SetSwitchRendererCallback() can be called from render_frame_impl.cc?

[xjz, 2016/10/01 00:28:41]

Done.

+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(MediaPlayerObserver);

[miu, 2016/09/30 08:12:10]

This doesn't belong in a pure virtual interface, since there's no reason to
restrict copying of a class that can't be instantiated.

[xjz, 2016/10/01 00:28:41]

Removed.

+};
+
+}  // namespace media
+
+#endif  // MEDIA_BASE_MEDIAPLAYER_OBSERVER_H_