Expose flash playback status and volume control to content renderer

content/renderer/pepper/pepper_audio_control_delegate.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_CONTROL_DELEGATE_H_
+#define CONTENT_RENDERER_PEPPER_PEPPER_AUDIO_CONTROL_DELEGATE_H_
+
+#include <set>
+
+#include "base/macros.h"
+
+namespace content {
+
+class PepperPluginInstanceImpl;
+class PPB_Audio_Impl;
+
+/**
+ * Class for delegating audio controls of a Pepper instance to all it's active
+ * audios.  This class can only be a non-sharable member of
+ * PepperPluginInstanceImpl.

[bbudge, 2016/06/22 18:14:55]

nits: s/it's/its
 s/audios/audio resources
 s/sharable/shareable

[Zhiqiang Zhang (Slow), 2016/06/22 21:00:42]

Done.

+ */
+class PepperAudioControlDelegate {

[bbudge, 2016/06/22 18:14:55]

This class seems more like a tracker / controller. 'PepperAudioControlDelegate'
is less clear to me than 'PepperAudioController' as a name.

[Zhiqiang Zhang (Slow), 2016/06/22 21:00:42]

Done.

+ public:
+  // Contructor of PepperAudioControlDelegate.
+  PepperAudioControlDelegate(PepperPluginInstanceImpl* pepper_instance);
+  // Destructor of PepperAudioControlDelegate, OnPepperInstanceDeleted() should
+  // be called before calling destructor.

[bbudge, 2016/06/22 18:14:55]

Instead of leaving it up to the client, why not automatically call
OnPepperInstanceDeleted? The destructor shouldn't need a comment then.

[Zhiqiang Zhang (Slow), 2016/06/22 21:00:43]

Done.

+  virtual ~PepperAudioControlDelegate();
+
+  // An audio instance has started playback.

[bbudge, 2016/06/22 18:14:55]

Comments should tell what method does, e.g.

// Adds an audio instance to the controller.

[Zhiqiang Zhang (Slow), 2016/06/22 21:00:42]

Done.

+  void AddActiveAudioInstance(PPB_Audio_Impl* audio);

[bbudge, 2016/06/22 18:14:55]

s/AddActiveAudioInstance/AddInstance should be enough.
Similarly for Remove.

[Zhiqiang Zhang (Slow), 2016/06/22 21:00:43]

Done.

+  // An audio instance has stopped playback.
+  void RemoveActiveAudioInstance(PPB_Audio_Impl* audio);
+  // Sets the volume of all delegated audios.

[bbudge, 2016/06/22 18:14:55]

s/audios/audio resources
Otherwise, comment is good

[Zhiqiang Zhang (Slow), 2016/06/22 21:00:42]

Done.

+  void SetVolume(double volume);
+  // The pepper instance has been deleted. This method can only be called
+  // once. The delegate will be invalidated after this call, and then all other
+  // methods will be no-op.
+  void OnPepperInstanceDeleted();
+
+ private:
+  // All active audio instances.
+  std::set<PPB_Audio_Impl*> ppb_audios_;
+  // The Pepper instance which this delegate is for. Will be null after
+  // OnPepperInstanceDeleted() is called.
+  PepperPluginInstanceImpl* pepper_instance_;

[bbudge, 2016/06/22 18:14:55]

s/pepper_instance_/instance_

Pepper should be obvious in this context.

[Zhiqiang Zhang (Slow), 2016/06/22 21:00:42]

Done.

+
+  DISALLOW_COPY_AND_ASSIGN(PepperAudioControlDelegate);
+};
+
+}
+
+#endif  // CONTENT_RENDERER_PEPPER_PEPPER_AUDIO_CONTROL_DELEGATE_H_