chromeos: Make system tray audio item observe CrasAudioHandler directly

ash/common/system/chromeos/audio/tray_audio.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_COMMON_SYSTEM_CHROMEOS_AUDIO_TRAY_AUDIO_H_
 #define ASH_COMMON_SYSTEM_CHROMEOS_AUDIO_TRAY_AUDIO_H_
 
 #include <stdint.h>
 
 #include <memory>
 
 #include "ash/ash_export.h"
-#include "ash/common/system/chromeos/audio/audio_observer.h"
 #include "ash/common/system/tray/tray_image_item.h"
 #include "base/macros.h"
+#include "chromeos/audio/cras_audio_handler.h"
 #include "chromeos/dbus/power_manager_client.h"
 #include "ui/display/display_observer.h"
 
 namespace ash {
 
 namespace system {
 class TrayAudioDelegate;
 }
 
 namespace tray {
 class AudioDetailedView;
 class VolumeView;
 }
 
 // The system tray item for audio input and output.
 class ASH_EXPORT TrayAudio : public TrayImageItem,
-                             public AudioObserver,
+                             public chromeos::CrasAudioHandler::AudioObserver,
                              public display::DisplayObserver,
                              public chromeos::PowerManagerClient::Observer {
  public:
   explicit TrayAudio(SystemTray* system_tray);
   ~TrayAudio() override;
 
+  // Temporarily shows the pop-up volume slider on all displays. Used by ARC++
+  // when an Android app changes the system volume.
+  static void ShowPopUpVolumeView();
+
+  tray::VolumeView* volume_view_for_testing() { return volume_view_; }
+  bool pop_up_volume_view_for_testing() { return pop_up_volume_view_; }
+
  private:
   // Overridden from display::DisplayObserver.
   void OnDisplayAdded(const display::Display& new_display) override;
   void OnDisplayRemoved(const display::Display& old_display) override;
   void OnDisplayMetricsChanged(const display::Display& display,
                                uint32_t changed_metrics) override;
 
   // Overridden from TrayImageItem.
   bool GetInitialVisibility() override;
 
   // Overridden from SystemTrayItem.
   views::View* CreateDefaultView(LoginStatus status) override;
   views::View* CreateDetailedView(LoginStatus status) override;
   void DestroyDefaultView() override;
   void DestroyDetailedView() override;
   bool ShouldHideArrow() const override;
   bool ShouldShowShelf() const override;
 
-  // Overridden from AudioObserver.
-  void OnOutputNodeVolumeChanged(uint64_t node_id, double volume) override;
+  // Overridden from CrasAudioHandler::AudioObserver.
+  void OnOutputNodeVolumeChanged(uint64_t node_id, int volume) override;
   void OnOutputMuteChanged(bool mute_on, bool system_adjust) override;
   void OnAudioNodesChanged() override;
   void OnActiveOutputNodeChanged() override;
   void OnActiveInputNodeChanged() override;
 
   // Overridden from chromeos::PowerManagerClient::Observer.
   void SuspendDone(const base::TimeDelta& sleep_duration) override;
 
   // Swaps the left and right channels on yoga devices based on orientation.
   void ChangeInternalSpeakerChannelMode();
@@ skipping 10 matching lines @@
   bool pop_up_volume_view_;
 
   tray::AudioDetailedView* audio_detail_view_;
 
   DISALLOW_COPY_AND_ASSIGN(TrayAudio);
 };
 
 }  // namespace ash
 
 #endif  // ASH_COMMON_SYSTEM_CHROMEOS_AUDIO_TRAY_AUDIO_H_