Implement new audio handler which talks to the new audio dbus apis.

chrome/browser/chromeos/audio/audio_pref_handler_impl.h

+// Copyright (c) 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 CHROME_BROWSER_CHROMEOS_AUDIO_AUDIO_PREF_HANDLER_IMPL_H_
+#define CHROME_BROWSER_CHROMEOS_AUDIO_AUDIO_PREF_HANDLER_IMPL_H_
+
+#include "base/observer_list.h"
+#include "base/prefs/pref_change_registrar.h"
+#include "chromeos/audio/audio_pref_handler.h"
+
+class PrefRegistrySimple;
+class PrefService;
+
+namespace chromeos {
+
+// Class which implements AudioPrefHandler interface and register audio

[Daniel Erat, 2013/04/18 20:55:22]

nit: s/register/registers/

saying "which implements AudioPrefHandler interface" here isn't very useful,
since the "class AudioPrefHandlerImpl : public AudioPrefHandler" line says the
same thing.

+// preferences as well.
+class AudioPrefHandlerImpl : public AudioPrefHandler {
+ public:
+  explicit AudioPrefHandlerImpl(PrefService* local_state);
+
+  // Overriden from AudioPreHandler.
+  virtual double GetOutputVolumeValue() OVERRIDE;
+  virtual void SetOutputVolumeValue(double volume_percent) OVERRIDE;
+  virtual bool GetOutputMuteValue() OVERRIDE;
+  virtual void SetOutputMuteValue(bool mute_on) OVERRIDE;
+  virtual bool GetAudioCaptureAllowedValue() OVERRIDE;
+  virtual bool GetAudioOutputAllowedValue() OVERRIDE;
+  virtual void AddAudioPrefObserver(AudioPrefObserver* observer) OVERRIDE;
+  virtual void RemoveAudioPrefObserver(AudioPrefObserver* observer) OVERRIDE;
+
+  // Registers volume and mute preferences.
+  static void RegisterPrefs(PrefRegistrySimple* registry);
+
+ protected:
+  virtual ~AudioPrefHandlerImpl();
+
+ private:
+  // Initializes the observers for the policy prefs.
+  void InitializePrefObservers();
+
+  // Notifies the AudioPrefObserver for audio policy pref changes.
+  void NotifyAudioPolicyChange();
+
+  PrefService* local_state_;  // not owned
+
+  PrefChangeRegistrar pref_change_registrar_;
+
+  ObserverList<AudioPrefObserver> observers_;
+
+  DISALLOW_COPY_AND_ASSIGN(AudioPrefHandlerImpl);
+};
+
+}  // namespace chromeos
+
+#endif  // CHROME_BROWSER_CHROMEOS_AUDIO_AUDIO_PREF_HANDLER_IMPL_H_