Fix the UI issue for showing output muted in ash tray after the device wakes up with hdmi output re…

ash/system/audio/audio_observer.h

 // Copyright 2014 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 ASH_SYSTEM_AUDIO_AUDIO_OBSERVER_H_
 #define ASH_SYSTEM_AUDIO_AUDIO_OBSERVER_H_
 
 #include <stdint.h>
 
 namespace ash {
 
 class AudioObserver {
  public:
   virtual ~AudioObserver() {}
 
   // Called when an active output device's volume changed.
   // |node_id|: id of the active node.
   // |volume|: volume as a percentage, 0.0 -- 100.0.
   virtual void OnOutputNodeVolumeChanged(uint64_t node_id, double volume) = 0;
 
   // Called when output mute state changed.
-  virtual void OnOutputMuteChanged(bool mute_on) = 0;
+  // |mute_on|: True if output is muted.
+  // |system_adjust|: True if the mute state is adjusted by the system
+  // automatically, UI should be consistent with the system's mute state,
+  // but it should not be too loud, e.g., the volume pop up window should not
+  // be triggered.
+  virtual void OnOutputMuteChanged(bool mute_on, bool system_adjust) = 0;
 
   // Called when audio nodes changed.
   virtual void OnAudioNodesChanged() = 0;
 
   // Called when active audio output node changed.
   virtual void OnActiveOutputNodeChanged() = 0;
 
   // Called when active audio input node changed.
   virtual void OnActiveInputNodeChanged() = 0;
 };
 
 }  // namespace ash
 
 #endif  // ASH_SYSTEM_AUDIO_AUDIO_OBSERVER_H_