Expose flash playback status and volume control to content renderer

content/renderer/pepper/pepper_audio_controller.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 CONTENT_RENDERER_PEPPER_PEPPER_AUDIO_CONTROLLER_H_
+#define CONTENT_RENDERER_PEPPER_PEPPER_AUDIO_CONTROLLER_H_
+
+#include <set>
+
+#include "base/macros.h"
+
+namespace content {
+
+class PepperPluginInstanceImpl;
+class PPB_Audio_Impl;
+
+/**
+ * Class for controlling all the active audio instances of a Pepper instance.
+ * This class can only be a non-shareable member of PepperPluginInstanceImpl.
+ */

[mlamouri (slow - plz ping), 2016/06/23 13:04:13]

style: we don't use /** comments. I think it should be:
```
// Class for controlling ...
// This class ...
```

[Zhiqiang Zhang (Slow), 2016/06/23 14:50:29]

Done.

+class PepperAudioController {
+ public:
+  // Contructor of PepperAudioController.
+  PepperAudioController(PepperPluginInstanceImpl* pepper_instance);

[mlamouri (slow - plz ping), 2016/06/23 13:04:13]

add explicit.

Also, I don't think the comment is super useful :)

[Zhiqiang Zhang (Slow), 2016/06/23 14:50:29]

Done.

+  // Destructor of PepperAudioController.

[mlamouri (slow - plz ping), 2016/06/23 13:04:13]

ditto for the comment :)

[Zhiqiang Zhang (Slow), 2016/06/23 14:50:29]

Done.

+  virtual ~PepperAudioController();
+
+  // Adds an audio instance to the controller.
+  void AddInstance(PPB_Audio_Impl* audio);
+  // Removes an audio instance from the controller.
+  void RemoveInstance(PPB_Audio_Impl* audio);
+  // Sets the volume of all delegated audio resources.
+  void SetVolume(double volume);
+  // The pepper instance has been deleted. This method can only be called
+  // once. The controller will be invalidated after this call, and then all
+  // other methods will be no-op.
+  void OnPepperInstanceDeleted();
+
+ private:
+  // Notifies the RenderFrame that the playback has stopped.  This method should
+  // only be called when |ppb_audios_| turns from non-empty to empty.
+  void NotifyPlaybackStopsOnEmpty();
+
+  // All active audio instances.
+  std::set<PPB_Audio_Impl*> ppb_audios_;
+  // The Pepper instance which this controller is for. Will be null after
+  // OnPepperInstanceDeleted() is called.
+  PepperPluginInstanceImpl* instance_;

[mlamouri (slow - plz ping), 2016/06/23 13:04:13]

style: leave an empty line between two methods or members

[Zhiqiang Zhang (Slow), 2016/06/23 14:50:29]

Done (and for all the methods above as well).

+
+  DISALLOW_COPY_AND_ASSIGN(PepperAudioController);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_RENDERER_PEPPER_PEPPER_AUDIO_CONTROLLER_H_