Resubmit 'Refactor the TrayAudio code so that it can be used by other platforms.'

This resubmission fixes a memory leak that was causing ASAN bots to fail.

Original code review: https://codereview.chromium.org/163953007

BUG=227247
R=jennyz@chromium.org
TBR=jamescook, jennyz

Review URL: https://codereview.chromium.org/165393013

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@252064 0039d316-1c4b-4281-b951-d872f2087c98

23 files changed, 1241 insertions, 691 deletions

diff --git a/ash/ash.gyp b/ash/ash.gyp
index a78d666..3b8d961 100644
--- a/ash/ash.gyp
+++ b/ash/ash.gyp
@@ -270,12 +270,22 @@
         'sticky_keys/sticky_keys_controller.h',
         'sticky_keys/sticky_keys_overlay.cc',
         'sticky_keys/sticky_keys_overlay.h',
+        'system/audio/audio_observer.h',
+        'system/audio/tray_audio.cc',
+        'system/audio/tray_audio.h',
+        'system/audio/tray_audio_delegate.h',
+        'system/audio/volume_view.cc',
+        'system/audio/volume_view.h',
         'system/bluetooth/bluetooth_observer.h',
         'system/bluetooth/tray_bluetooth.cc',
         'system/bluetooth/tray_bluetooth.h',
         'system/brightness_control_delegate.h',
-        'system/chromeos/audio/tray_audio.cc',
-        'system/chromeos/audio/tray_audio.h',
+        'system/chromeos/audio/audio_detailed_view.cc',
+        'system/chromeos/audio/audio_detailed_view.h',
+        'system/chromeos/audio/tray_audio_chromeos.cc',
+        'system/chromeos/audio/tray_audio_chromeos.h',
+        'system/chromeos/audio/tray_audio_delegate_chromeos.cc',
+        'system/chromeos/audio/tray_audio_delegate_chromeos.h',
         'system/chromeos/enterprise/enterprise_domain_observer.h',
         'system/chromeos/brightness/brightness_controller_chromeos.cc',
         'system/chromeos/brightness/brightness_controller_chromeos.h',
diff --git a/ash/ash_switches.cc b/ash/ash_switches.cc
index 1241344..735bda0 100644
--- a/ash/ash_switches.cc
+++ b/ash/ash_switches.cc
@@ -256,12 +256,16 @@ bool UseDockedWindows() {
   return !CommandLine::ForCurrentProcess()->HasSwitch(kAshDisableDockedWindows);
 }
 
-#if defined(OS_CHROMEOS)
 bool ShowAudioDeviceMenu() {
+#if defined(OS_CHROMEOS)
   return !CommandLine::ForCurrentProcess()->
       HasSwitch(kAshDisableAudioDeviceMenu);
+#else
+  return false;
+#endif
 }
 
+#if defined(OS_CHROMEOS)
 bool UseUsbChargerNotification() {
   return !CommandLine::ForCurrentProcess()->
       HasSwitch(kAshDisableUsbChargerNotification);
diff --git a/ash/ash_switches.h b/ash/ash_switches.h
index 80181c9..bf19557 100644
--- a/ash/ash_switches.h
+++ b/ash/ash_switches.h
@@ -101,10 +101,10 @@ ASH_EXPORT bool UseOverviewMode();
 // Returns true if docked windows feature is enabled.
 ASH_EXPORT bool UseDockedWindows();
 
-#if defined(OS_CHROMEOS)
 // Returns true if we should show the audio device switching UI.
 ASH_EXPORT bool ShowAudioDeviceMenu();
 
+#if defined(OS_CHROMEOS)
 // Returns true if a notification should appear when a low-power USB charger
 // is connected.
 ASH_EXPORT bool UseUsbChargerNotification();
diff --git a/ash/system/audio/audio_observer.h b/ash/system/audio/audio_observer.h
new file mode 100644
index 0000000..6023226
--- /dev/null
+++ b/ash/system/audio/audio_observer.h
@@ -0,0 +1,32 @@
+// 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_
+
+namespace ash {
+
+class AudioObserver {
+ public:
+  virtual ~AudioObserver() {}
+
+  // Called when output volume changed.
+  virtual void OnOutputVolumeChanged() = 0;
+
+  // Called when output mute state changed.
+  virtual void OnOutputMuteChanged() = 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_
diff --git a/ash/system/audio/tray_audio.cc b/ash/system/audio/tray_audio.cc
new file mode 100644
index 0000000..1a35514
--- /dev/null
+++ b/ash/system/audio/tray_audio.cc
@@ -0,0 +1,143 @@
+// 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.
+
+#include "ash/system/audio/tray_audio.h"
+
+#include <cmath>
+
+#include "ash/ash_constants.h"
+#include "ash/ash_switches.h"
+#include "ash/metrics/user_metrics_recorder.h"
+#include "ash/shell.h"
+#include "ash/system/audio/tray_audio_delegate.h"
+#include "ash/system/audio/volume_view.h"
+#include "ash/system/tray/actionable_view.h"
+#include "ash/system/tray/fixed_sized_scroll_view.h"
+#include "ash/system/tray/hover_highlight_view.h"
+#include "ash/system/tray/system_tray.h"
+#include "ash/system/tray/system_tray_delegate.h"
+#include "ash/system/tray/system_tray_notifier.h"
+#include "ash/system/tray/tray_constants.h"
+#include "ash/volume_control_delegate.h"
+#include "base/strings/utf_string_conversions.h"
+#include "grit/ash_resources.h"
+#include "grit/ash_strings.h"
+#include "third_party/skia/include/core/SkCanvas.h"
+#include "third_party/skia/include/core/SkPaint.h"
+#include "third_party/skia/include/core/SkRect.h"
+#include "third_party/skia/include/effects/SkGradientShader.h"
+#include "ui/base/l10n/l10n_util.h"
+#include "ui/base/resource/resource_bundle.h"
+#include "ui/gfx/canvas.h"
+#include "ui/gfx/font_list.h"
+#include "ui/gfx/image/image.h"
+#include "ui/gfx/image/image_skia_operations.h"
+#include "ui/views/controls/button/image_button.h"
+#include "ui/views/controls/image_view.h"
+#include "ui/views/controls/label.h"
+#include "ui/views/controls/slider.h"
+#include "ui/views/layout/box_layout.h"
+#include "ui/views/view.h"
+
+namespace ash {
+namespace internal {
+
+TrayAudio::TrayAudio(SystemTray* system_tray,
+                     scoped_ptr<system::TrayAudioDelegate> audio_delegate)
+    : TrayImageItem(system_tray, IDR_AURA_UBER_TRAY_VOLUME_MUTE),
+      audio_delegate_(audio_delegate.Pass()),
+      volume_view_(NULL),
+      pop_up_volume_view_(false) {
+  Shell::GetInstance()->system_tray_notifier()->AddAudioObserver(this);
+}
+
+TrayAudio::~TrayAudio() {
+  Shell::GetInstance()->system_tray_notifier()->RemoveAudioObserver(this);
+}
+
+bool TrayAudio::GetInitialVisibility() {
+  return audio_delegate_->IsOutputAudioMuted();
+}
+
+views::View* TrayAudio::CreateDefaultView(user::LoginStatus status) {
+  volume_view_ = new tray::VolumeView(this, audio_delegate_.get(), true);
+  return volume_view_;
+}
+
+views::View* TrayAudio::CreateDetailedView(user::LoginStatus status) {
+  volume_view_ = new tray::VolumeView(this, audio_delegate_.get(), false);
+  return volume_view_;
+}
+
+void TrayAudio::DestroyDefaultView() {
+  volume_view_ = NULL;
+}
+
+void TrayAudio::DestroyDetailedView() {
+  if (volume_view_) {
+    volume_view_ = NULL;
+    pop_up_volume_view_ = false;
+  }
+}
+
+bool TrayAudio::ShouldHideArrow() const {
+  return true;
+}
+
+bool TrayAudio::ShouldShowShelf() const {
+  return ash::switches::ShowAudioDeviceMenu() && !pop_up_volume_view_;
+}
+
+void TrayAudio::OnOutputVolumeChanged() {
+  float percent =
+      static_cast<float>(audio_delegate_->GetOutputVolumeLevel()) / 100.0f;
+  if (tray_view())
+    tray_view()->SetVisible(GetInitialVisibility());
+
+  if (volume_view_) {
+    volume_view_->SetVolumeLevel(percent);
+    SetDetailedViewCloseDelay(kTrayPopupAutoCloseDelayInSeconds);
+    return;
+  }
+  pop_up_volume_view_ = true;
+  PopupDetailedView(kTrayPopupAutoCloseDelayInSeconds, false);
+}
+
+void TrayAudio::OnOutputMuteChanged() {
+  if (tray_view())
+      tray_view()->SetVisible(GetInitialVisibility());
+
+  if (volume_view_) {
+    volume_view_->Update();
+    SetDetailedViewCloseDelay(kTrayPopupAutoCloseDelayInSeconds);
+  } else {
+    pop_up_volume_view_ = true;
+    PopupDetailedView(kTrayPopupAutoCloseDelayInSeconds, false);
+  }
+}
+
+void TrayAudio::OnAudioNodesChanged() {
+  Update();
+}
+
+void TrayAudio::OnActiveOutputNodeChanged() {
+  Update();
+}
+
+void TrayAudio::OnActiveInputNodeChanged() {
+  Update();
+}
+
+void TrayAudio::Update() {
+  if (tray_view())
+      tray_view()->SetVisible(GetInitialVisibility());
+  if (volume_view_) {
+    volume_view_->SetVolumeLevel(
+        static_cast<float>(audio_delegate_->GetOutputVolumeLevel()) / 100.0f);
+    volume_view_->Update();
+  }
+}
+
+}  // namespace internal
+}  // namespace ash
diff --git a/ash/system/chromeos/audio/tray_audio.h b/ash/system/audio/tray_audio.h
index eb6e117a..923245a 100644
--- a/ash/system/chromeos/audio/tray_audio.h
+++ b/ash/system/audio/tray_audio.h
@@ -1,27 +1,43 @@
-// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// 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_CHROMEOS_AUDIO_TRAY_AUDIO_H_
-#define ASH_SYSTEM_CHROMEOS_AUDIO_TRAY_AUDIO_H_
+#ifndef ASH_SYSTEM_AUDIO_TRAY_AUDIO_H_
+#define ASH_SYSTEM_AUDIO_TRAY_AUDIO_H_
 
+#include "ash/system/audio/audio_observer.h"
 #include "ash/system/tray/tray_image_item.h"
-#include "chromeos/audio/cras_audio_handler.h"
+#include "base/memory/scoped_ptr.h"
 
 namespace ash {
+
+namespace system {
+class TrayAudioDelegate;
+}
+
 namespace internal {
 
 namespace tray {
 class VolumeView;
-class AudioDetailedView;
 }
 
 class TrayAudio : public TrayImageItem,
-                  public chromeos::CrasAudioHandler::AudioObserver {
+                  public AudioObserver {
  public:
-  explicit TrayAudio(SystemTray* system_tray);
+  TrayAudio(SystemTray* system_tray,
+            scoped_ptr<system::TrayAudioDelegate> audio_delegate);
   virtual ~TrayAudio();
 
+ protected:
+  virtual void Update();
+
+  scoped_ptr<system::TrayAudioDelegate> audio_delegate_;
+  tray::VolumeView* volume_view_;
+
+  // True if VolumeView should be created for accelerator pop up;
+  // Otherwise, it should be created for detailed view in ash tray bubble.
+  bool pop_up_volume_view_;
+
  private:
   // Overridden from TrayImageItem.
   virtual bool GetInitialVisibility() OVERRIDE;
@@ -34,28 +50,17 @@ class TrayAudio : public TrayImageItem,
   virtual bool ShouldHideArrow() const OVERRIDE;
   virtual bool ShouldShowShelf() const OVERRIDE;
 
-  // Overridden from chromeos::CrasAudioHandler::AudioObserver.
+  // Overridden from AudioObserver.
   virtual void OnOutputVolumeChanged() OVERRIDE;
   virtual void OnOutputMuteChanged() OVERRIDE;
-  virtual void OnInputGainChanged() OVERRIDE;
-  virtual void OnInputMuteChanged() OVERRIDE;
   virtual void OnAudioNodesChanged() OVERRIDE;
   virtual void OnActiveOutputNodeChanged() OVERRIDE;
   virtual void OnActiveInputNodeChanged() OVERRIDE;
 
-  void Update();
-
-  tray::VolumeView* volume_view_;
-  tray::AudioDetailedView* audio_detail_;
-
-  // True if VolumeView should be created for accelerator pop up;
-  // Otherwise, it should be created for detailed view in ash tray bubble.
-  bool pop_up_volume_view_;
-
   DISALLOW_COPY_AND_ASSIGN(TrayAudio);
 };
 
 }  // namespace internal
 }  // namespace ash
 
-#endif  // ASH_SYSTEM_CHROMEOS_AUDIO_TRAY_AUDIO_H_
+#endif  // ASH_SYSTEM_AUDIO_TRAY_AUDIO_H_
diff --git a/ash/system/audio/tray_audio_delegate.h b/ash/system/audio/tray_audio_delegate.h
new file mode 100644
index 0000000..823bfff
--- /dev/null
+++ b/ash/system/audio/tray_audio_delegate.h
@@ -0,0 +1,48 @@
+// 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_TRAY_AUDIO_DELEGATE_H_
+#define ASH_SYSTEM_AUDIO_TRAY_AUDIO_DELEGATE_H_
+
+namespace ash {
+namespace system {
+
+class TrayAudioDelegate {
+ public:
+
+  enum { kNoAudioDeviceIcon = -1 };
+
+  virtual ~TrayAudioDelegate() {}
+
+  // Sets the volume level of the output device to the minimum level which is
+  // deemed to be audible.
+  virtual void AdjustOutputVolumeToAudibleLevel() = 0;
+
+  // Gets the default level in the range 0%-100% at which the output device
+  // should be muted.
+  virtual int GetOutputDefaultVolumeMuteLevel() = 0;
+
+  // Gets the icon to use for the active output device.
+  virtual int GetActiveOutputDeviceIconId() = 0;
+
+  // Returns the volume level of the output device in the range 0%-100%.
+  virtual int GetOutputVolumeLevel() = 0;
+
+  // Returns true if the device has alternative inputs or outputs.
+  virtual bool HasAlternativeSources() = 0;
+
+  // Returns whether the output volume is muted.
+  virtual bool IsOutputAudioMuted() = 0;
+
+  // Sets the mute state of the output device.
+  virtual void SetOutputAudioIsMuted(bool is_muted) = 0;
+
+  // Sets the volume level of the output device in the range 0%-100%
+  virtual void SetOutputVolumeLevel(int level) = 0;
+};
+
+}  // namespace system
+}  // namespace ash
+
+#endif  // ASH_SYSTEM_AUDIO_TRAY_AUDIO_DELEGATE_H_
diff --git a/ash/system/audio/volume_view.cc b/ash/system/audio/volume_view.cc
new file mode 100644
index 0000000..5cb3970
--- /dev/null
+++ b/ash/system/audio/volume_view.cc
@@ -0,0 +1,332 @@
+// 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.
+
+#include "ash/system/audio/volume_view.h"
+
+#include "ash/ash_constants.h"
+#include "ash/ash_switches.h"
+#include "ash/shell.h"
+#include "ash/system/audio/tray_audio_delegate.h"
+#include "ash/system/tray/system_tray_item.h"
+#include "ash/system/tray/tray_constants.h"
+#include "grit/ash_resources.h"
+#include "grit/ash_strings.h"
+#include "ui/base/resource/resource_bundle.h"
+#include "ui/gfx/canvas.h"
+#include "ui/gfx/image/image_skia_operations.h"
+#include "ui/views/controls/button/image_button.h"
+#include "ui/views/controls/image_view.h"
+#include "ui/views/layout/box_layout.h"
+
+namespace {
+const int kVolumeImageWidth = 25;
+const int kVolumeImageHeight = 25;
+const int kBarSeparatorWidth = 25;
+const int kBarSeparatorHeight = 30;
+const int kSliderRightPaddingToVolumeViewEdge = 17;
+const int kExtraPaddingBetweenBarAndMore = 10;
+
+// IDR_AURA_UBER_TRAY_VOLUME_LEVELS contains 5 images,
+// The one for mute is at the 0 index and the other
+// four are used for ascending volume levels.
+const int kVolumeLevels = 4;
+
+}  // namespace
+
+namespace ash {
+namespace internal {
+namespace tray {
+
+class VolumeButton : public views::ToggleImageButton {
+ public:
+   VolumeButton(views::ButtonListener* listener,
+                system::TrayAudioDelegate* audio_delegate)
+      : views::ToggleImageButton(listener),
+        audio_delegate_(audio_delegate),
+        image_index_(-1) {
+    SetImageAlignment(ALIGN_CENTER, ALIGN_MIDDLE);
+    image_ = ui::ResourceBundle::GetSharedInstance().GetImageNamed(
+        IDR_AURA_UBER_TRAY_VOLUME_LEVELS);
+    SetPreferredSize(gfx::Size(kTrayPopupItemHeight, kTrayPopupItemHeight));
+    Update();
+  }
+
+  virtual ~VolumeButton() {}
+
+  void Update() {
+    float level =
+        static_cast<float>(audio_delegate_->GetOutputVolumeLevel()) / 100.0f;
+    int image_index = audio_delegate_->IsOutputAudioMuted() ?
+        0 : (level == 1.0 ?
+             kVolumeLevels :
+             std::max(1, int(std::ceil(level * (kVolumeLevels - 1)))));
+    if (image_index != image_index_) {
+      gfx::Rect region(0, image_index * kVolumeImageHeight,
+                       kVolumeImageWidth, kVolumeImageHeight);
+      gfx::ImageSkia image_skia = gfx::ImageSkiaOperations::ExtractSubset(
+          *(image_.ToImageSkia()), region);
+      SetImage(views::CustomButton::STATE_NORMAL, &image_skia);
+      image_index_ = image_index;
+    }
+    SchedulePaint();
+  }
+
+ private:
+  // Overridden from views::View.
+  virtual gfx::Size GetPreferredSize() OVERRIDE {
+    gfx::Size size = views::ToggleImageButton::GetPreferredSize();
+    size.set_height(kTrayPopupItemHeight);
+    return size;
+  }
+
+  system::TrayAudioDelegate* audio_delegate_;
+  gfx::Image image_;
+  int image_index_;
+
+  DISALLOW_COPY_AND_ASSIGN(VolumeButton);
+};
+
+class VolumeSlider : public views::Slider {
+ public:
+  VolumeSlider(views::SliderListener* listener,
+               system::TrayAudioDelegate* audio_delegate)
+      : views::Slider(listener, views::Slider::HORIZONTAL),
+        audio_delegate_(audio_delegate) {
+    set_focus_border_color(kFocusBorderColor);
+    SetValue(
+        static_cast<float>(audio_delegate_->GetOutputVolumeLevel()) / 100.0f);
+    SetAccessibleName(
+            ui::ResourceBundle::GetSharedInstance().GetLocalizedString(
+                IDS_ASH_STATUS_TRAY_VOLUME));
+    Update();
+  }
+  virtual ~VolumeSlider() {}
+
+  void Update() {
+    UpdateState(!audio_delegate_->IsOutputAudioMuted());
+  }
+
+ private:
+  system::TrayAudioDelegate* audio_delegate_;
+
+  DISALLOW_COPY_AND_ASSIGN(VolumeSlider);
+};
+
+// Vertical bar separator that can be placed on the VolumeView.
+class BarSeparator : public views::View {
+ public:
+  BarSeparator() {}
+  virtual ~BarSeparator() {}
+
+  // Overriden from views::View.
+  virtual gfx::Size GetPreferredSize() OVERRIDE {
+    return gfx::Size(kBarSeparatorWidth, kBarSeparatorHeight);
+  }
+
+ private:
+  virtual void OnPaint(gfx::Canvas* canvas) OVERRIDE {
+    canvas->FillRect(gfx::Rect(width() / 2, 0, 1, height()),
+                     kButtonStrokeColor);
+  }
+
+  DISALLOW_COPY_AND_ASSIGN(BarSeparator);
+};
+
+VolumeView::VolumeView(SystemTrayItem* owner,
+                       system::TrayAudioDelegate* audio_delegate,
+                       bool is_default_view)
+    : owner_(owner),
+      audio_delegate_(audio_delegate),
+      icon_(NULL),
+      slider_(NULL),
+      bar_(NULL),
+      device_type_(NULL),
+      more_(NULL),
+      is_default_view_(is_default_view) {
+  SetFocusable(false);
+  SetLayoutManager(new views::BoxLayout(views::BoxLayout::kHorizontal,
+        kTrayPopupPaddingHorizontal, 0, kTrayPopupPaddingBetweenItems));
+
+  icon_ = new VolumeButton(this, audio_delegate_);
+  AddChildView(icon_);
+
+  slider_ = new VolumeSlider(this, audio_delegate_);
+  AddChildView(slider_);
+
+  bar_ = new BarSeparator;
+  AddChildView(bar_);
+
+  device_type_ = new views::ImageView;
+  AddChildView(device_type_);
+
+  more_ = new views::ImageView;
+  more_->EnableCanvasFlippingForRTLUI(true);
+  more_->SetImage(ui::ResourceBundle::GetSharedInstance().GetImageNamed(
+      IDR_AURA_UBER_TRAY_MORE).ToImageSkia());
+  AddChildView(more_);
+
+  Update();
+}
+
+VolumeView::~VolumeView() {
+}
+
+void VolumeView::Update() {
+  icon_->Update();
+  slider_->Update();
+  UpdateDeviceTypeAndMore();
+  Layout();
+}
+
+void VolumeView::SetVolumeLevel(float percent) {
+  // Slider's value is in finer granularity than audio volume level(0.01),
+  // there will be a small discrepancy between slider's value and volume level
+  // on audio side. To avoid the jittering in slider UI, do not set change
+  // slider value if the change is less than 1%.
+  if (std::abs(percent-slider_->value()) < 0.01)
+    return;
+  // The change in volume will be reflected via accessibility system events,
+  // so we prevent the UI event from being sent here.
+  slider_->set_enable_accessibility_events(false);
+  slider_->SetValue(percent);
+  // It is possible that the volume was (un)muted, but the actual volume level
+  // did not change. In that case, setting the value of the slider won't
+  // trigger an update. So explicitly trigger an update.
+  Update();
+  slider_->set_enable_accessibility_events(true);
+}
+
+void VolumeView::UpdateDeviceTypeAndMore() {
+  if (!ash::switches::ShowAudioDeviceMenu() || !is_default_view_) {
+    more_->SetVisible(false);
+    bar_->SetVisible(false);
+    device_type_->SetVisible(false);
+    return;
+  }
+
+  bool show_more = audio_delegate_->HasAlternativeSources();
+  more_->SetVisible(show_more);
+  bar_->SetVisible(show_more);
+
+  // Show output device icon if necessary.
+  int device_icon = audio_delegate_->GetActiveOutputDeviceIconId();
+  if (device_icon != system::TrayAudioDelegate::kNoAudioDeviceIcon) {
+    device_type_->SetVisible(true);
+    device_type_->SetImage(
+        ui::ResourceBundle::GetSharedInstance().GetImageNamed(
+            device_icon).ToImageSkia());
+  } else {
+    device_type_->SetVisible(false);
+  }
+}
+
+void VolumeView::HandleVolumeUp(float level) {
+  audio_delegate_->SetOutputVolumeLevel(level);
+  if (audio_delegate_->IsOutputAudioMuted() &&
+      level > audio_delegate_->GetOutputDefaultVolumeMuteLevel()) {
+    audio_delegate_->SetOutputAudioIsMuted(false);
+  }
+}
+
+void VolumeView::HandleVolumeDown(float level) {
+  audio_delegate_->SetOutputVolumeLevel(level);
+  if (!audio_delegate_->IsOutputAudioMuted() &&
+      level <= audio_delegate_->GetOutputDefaultVolumeMuteLevel()) {
+    audio_delegate_->SetOutputAudioIsMuted(true);
+  } else if (audio_delegate_->IsOutputAudioMuted() &&
+             level > audio_delegate_->GetOutputDefaultVolumeMuteLevel()) {
+    audio_delegate_->SetOutputAudioIsMuted(false);
+  }
+}
+
+void VolumeView::Layout() {
+  views::View::Layout();
+
+  if (!more_->visible()) {
+    int w = width() - slider_->bounds().x() -
+            kSliderRightPaddingToVolumeViewEdge;
+    slider_->SetSize(gfx::Size(w, slider_->height()));
+    return;
+  }
+
+  // Make sure the chevron always has the full size.
+  gfx::Size size = more_->GetPreferredSize();
+  gfx::Rect bounds(size);
+  bounds.set_x(width() - size.width() - kTrayPopupPaddingBetweenItems);
+  bounds.set_y((height() - size.height()) / 2);
+  more_->SetBoundsRect(bounds);
+
+  // Layout either bar_ or device_type_ at the left of the more_ button.
+  views::View* view_left_to_more;
+  if (device_type_->visible())
+    view_left_to_more = device_type_;
+  else
+    view_left_to_more = bar_;
+  gfx::Size view_size = view_left_to_more->GetPreferredSize();
+  gfx::Rect view_bounds(view_size);
+  view_bounds.set_x(more_->bounds().x() - view_size.width() -
+                    kExtraPaddingBetweenBarAndMore);
+  view_bounds.set_y((height() - view_size.height()) / 2);
+  view_left_to_more->SetBoundsRect(view_bounds);
+
+  // Layout vertical bar next to view_left_to_more if device_type_ is visible.
+  if (device_type_->visible()) {
+    gfx::Size bar_size = bar_->GetPreferredSize();
+    gfx::Rect bar_bounds(bar_size);
+    bar_bounds.set_x(view_left_to_more->bounds().x() - bar_size.width());
+    bar_bounds.set_y((height() - bar_size.height()) / 2);
+    bar_->SetBoundsRect(bar_bounds);
+  }
+
+  // Layout slider, calculate slider width.
+  gfx::Rect slider_bounds = slider_->bounds();
+  slider_bounds.set_width(
+      bar_->bounds().x()
+      - (device_type_->visible() ? 0 : kTrayPopupPaddingBetweenItems)
+      - slider_bounds.x());
+  slider_->SetBoundsRect(slider_bounds);
+}
+
+void VolumeView::ButtonPressed(views::Button* sender, const ui::Event& event) {
+  CHECK(sender == icon_);
+  bool mute_on = !audio_delegate_->IsOutputAudioMuted();
+  audio_delegate_->SetOutputAudioIsMuted(mute_on);
+  if (!mute_on)
+    audio_delegate_->AdjustOutputVolumeToAudibleLevel();
+  icon_->Update();
+}
+
+void VolumeView::SliderValueChanged(views::Slider* sender,
+                                    float value,
+                                    float old_value,
+                                    views::SliderChangeReason reason) {
+  if (reason == views::VALUE_CHANGED_BY_USER) {
+    float new_volume = value * 100.0f;
+    float current_volume = audio_delegate_->GetOutputVolumeLevel();
+    // Do not call change audio volume if the difference is less than
+    // 1%, which is beyond cras audio api's granularity for output volume.
+    if (std::abs(new_volume - current_volume) < 1.0f)
+      return;
+    Shell::GetInstance()->metrics()->RecordUserMetricsAction(
+        is_default_view_ ?
+        ash::UMA_STATUS_AREA_CHANGED_VOLUME_MENU :
+        ash::UMA_STATUS_AREA_CHANGED_VOLUME_POPUP);
+    if (new_volume > current_volume)
+      HandleVolumeUp(new_volume);
+    else
+      HandleVolumeDown(new_volume);
+  }
+  icon_->Update();
+}
+
+bool VolumeView::PerformAction(const ui::Event& event) {
+  if (!more_->visible())
+    return false;
+  owner_->TransitionDetailedView();
+  return true;
+}
+
+}  // namespace tray
+}  // namespace internal
+}  // namespace ash
diff --git a/ash/system/audio/volume_view.h b/ash/system/audio/volume_view.h
new file mode 100644
index 0000000..a3e8291
--- /dev/null
+++ b/ash/system/audio/volume_view.h
@@ -0,0 +1,90 @@
+// 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_VOLUME_VIEW_H_
+#define ASH_SYSTEM_AUDIO_VOLUME_VIEW_H_
+
+#include "ash/system/tray/actionable_view.h"
+#include "ui/gfx/font.h"
+#include "ui/views/controls/button/button.h"
+#include "ui/views/controls/slider.h"
+
+namespace views {
+class View;
+class ImageView;
+}
+
+namespace ash {
+
+class SystemTrayItem;
+
+namespace system {
+class TrayAudioDelegate;
+}
+
+namespace internal {
+
+class HoverHighlightView;
+
+namespace tray {
+
+class BarSeparator;
+class VolumeButton;
+class VolumeSlider;
+
+class VolumeView : public ActionableView,
+                   public views::ButtonListener,
+                   public views::SliderListener {
+ public:
+  VolumeView(SystemTrayItem* owner,
+             system::TrayAudioDelegate* audio_delegate,
+             bool is_default_view);
+
+  virtual ~VolumeView();
+
+  void Update();
+
+  // Sets volume level on slider_, |percent| is ranged from [0.00] to [1.00].
+  void SetVolumeLevel(float percent);
+
+ private:
+  // Updates bar_, device_type_ icon, and more_ buttons.
+  void UpdateDeviceTypeAndMore();
+  void HandleVolumeUp(float percent);
+  void HandleVolumeDown(float percent);
+
+  // Overridden from views::View.
+  virtual void Layout() OVERRIDE;
+
+  // Overridden from views::ButtonListener.
+  virtual void ButtonPressed(views::Button* sender,
+                             const ui::Event& event) OVERRIDE;
+
+  // Overridden from views::SliderListener.
+  virtual void SliderValueChanged(views::Slider* sender,
+                                  float value,
+                                  float old_value,
+                                  views::SliderChangeReason reason) OVERRIDE;
+
+  // Overriden from ActionableView.
+  virtual bool PerformAction(const ui::Event& event) OVERRIDE;
+
+  SystemTrayItem* owner_;
+  system::TrayAudioDelegate* audio_delegate_;
+  VolumeButton* icon_;
+  VolumeSlider* slider_;
+  BarSeparator* bar_;
+  views::ImageView* device_type_;
+  views::ImageView* more_;
+  bool is_default_view_;
+
+  DISALLOW_COPY_AND_ASSIGN(VolumeView);
+};
+
+}  // namespace tray
+}  // namespace internal
+}  // namespace ash
+
+#endif  // ASH_SYSTEM_AUDIO_VOLUME_VIEW_H_
+
diff --git a/ash/system/chromeos/audio/audio_detailed_view.cc b/ash/system/chromeos/audio/audio_detailed_view.cc
new file mode 100644
index 0000000..803f4dd
--- /dev/null
+++ b/ash/system/chromeos/audio/audio_detailed_view.cc
@@ -0,0 +1,177 @@
+// 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.
+
+#include "ash/system/chromeos/audio/audio_detailed_view.h"
+
+#include "ash/system/tray/fixed_sized_scroll_view.h"
+#include "ash/system/tray/hover_highlight_view.h"
+#include "ash/system/tray/tray_constants.h"
+#include "base/strings/utf_string_conversions.h"
+#include "chromeos/audio/cras_audio_handler.h"
+#include "grit/ash_resources.h"
+#include "grit/ash_strings.h"
+#include "ui/base/l10n/l10n_util.h"
+#include "ui/base/resource/resource_bundle.h"
+#include "ui/views/border.h"
+#include "ui/views/controls/label.h"
+
+namespace {
+
+base::string16 GetAudioDeviceName(const chromeos::AudioDevice& device) {
+  switch(device.type) {
+    case chromeos::AUDIO_TYPE_HEADPHONE:
+      return l10n_util::GetStringUTF16(IDS_ASH_STATUS_TRAY_AUDIO_HEADPHONE);
+    case chromeos::AUDIO_TYPE_INTERNAL_SPEAKER:
+      return l10n_util::GetStringUTF16(
+          IDS_ASH_STATUS_TRAY_AUDIO_INTERNAL_SPEAKER);
+    case chromeos::AUDIO_TYPE_INTERNAL_MIC:
+      return l10n_util::GetStringUTF16(IDS_ASH_STATUS_TRAY_AUDIO_INTERNAL_MIC);
+    case chromeos::AUDIO_TYPE_USB:
+      return l10n_util::GetStringFUTF16(
+          IDS_ASH_STATUS_TRAY_AUDIO_USB_DEVICE,
+          base::UTF8ToUTF16(device.display_name));
+    case chromeos::AUDIO_TYPE_BLUETOOTH:
+      return l10n_util::GetStringFUTF16(
+          IDS_ASH_STATUS_TRAY_AUDIO_BLUETOOTH_DEVICE,
+          base::UTF8ToUTF16(device.display_name));
+    case chromeos::AUDIO_TYPE_HDMI:
+      return l10n_util::GetStringFUTF16(
+          IDS_ASH_STATUS_TRAY_AUDIO_HDMI_DEVICE,
+          base::UTF8ToUTF16(device.display_name));
+    default:
+      return base::UTF8ToUTF16(device.display_name);
+  }
+}
+
+}  // namespace
+
+using chromeos::CrasAudioHandler;
+
+namespace ash {
+namespace internal {
+namespace tray {
+
+AudioDetailedView::AudioDetailedView(SystemTrayItem* owner,
+                                     user::LoginStatus login)
+    : TrayDetailsView(owner),
+      login_(login) {
+  CreateItems();
+  Update();
+}
+
+AudioDetailedView::~AudioDetailedView() {
+}
+
+void AudioDetailedView::Update() {
+  UpdateAudioDevices();
+  Layout();
+}
+
+void AudioDetailedView::AddScrollListInfoItem(const base::string16& text) {
+  views::Label* label = new views::Label(
+      text,
+      ui::ResourceBundle::GetSharedInstance().GetFontList(
+          ui::ResourceBundle::BoldFont));
+
+  //  Align info item with checkbox items
+  int margin = kTrayPopupPaddingHorizontal +
+      kTrayPopupDetailsLabelExtraLeftMargin;
+  int left_margin = 0;
+  int right_margin = 0;
+  if (base::i18n::IsRTL())
+    right_margin = margin;
+  else
+    left_margin = margin;
+
+  label->SetBorder(views::Border::CreateEmptyBorder(
+      ash::kTrayPopupPaddingBetweenItems,
+      left_margin,
+      ash::kTrayPopupPaddingBetweenItems,
+      right_margin));
+  label->SetHorizontalAlignment(gfx::ALIGN_LEFT);
+  label->SetEnabledColor(SkColorSetARGB(192, 0, 0, 0));
+
+  scroll_content()->AddChildView(label);
+}
+
+HoverHighlightView* AudioDetailedView::AddScrollListItem(
+    const base::string16& text,
+    gfx::Font::FontStyle style,
+    bool checked) {
+  HoverHighlightView* container = new HoverHighlightView(this);
+  container->AddCheckableLabel(text, style, checked);
+  scroll_content()->AddChildView(container);
+  return container;
+}
+
+void AudioDetailedView::CreateHeaderEntry() {
+  CreateSpecialRow(IDS_ASH_STATUS_TRAY_AUDIO, this);
+}
+
+void AudioDetailedView::CreateItems() {
+  CreateScrollableList();
+  CreateHeaderEntry();
+}
+
+void AudioDetailedView::UpdateAudioDevices() {
+  output_devices_.clear();
+  input_devices_.clear();
+  chromeos::AudioDeviceList devices;
+  CrasAudioHandler::Get()->GetAudioDevices(&devices);
+  for (size_t i = 0; i < devices.size(); ++i) {
+    if (devices[i].is_input)
+      input_devices_.push_back(devices[i]);
+    else
+      output_devices_.push_back(devices[i]);
+  }
+  UpdateScrollableList();
+}
+
+void AudioDetailedView::UpdateScrollableList() {
+  scroll_content()->RemoveAllChildViews(true);
+  device_map_.clear();
+
+  // Add audio output devices.
+  AddScrollListInfoItem(
+      l10n_util::GetStringUTF16(IDS_ASH_STATUS_TRAY_AUDIO_OUTPUT));
+  for (size_t i = 0; i < output_devices_.size(); ++i) {
+    HoverHighlightView* container = AddScrollListItem(
+        GetAudioDeviceName(output_devices_[i]),
+        gfx::Font::NORMAL,
+        output_devices_[i].active);  /* checkmark if active */
+    device_map_[container] = output_devices_[i];
+  }
+
+  AddScrollSeparator();
+
+  // Add audio input devices.
+  AddScrollListInfoItem(
+      l10n_util::GetStringUTF16(IDS_ASH_STATUS_TRAY_AUDIO_INPUT));
+  for (size_t i = 0; i < input_devices_.size(); ++i) {
+    HoverHighlightView* container = AddScrollListItem(
+        GetAudioDeviceName(input_devices_[i]),
+        gfx::Font::NORMAL,
+        input_devices_[i].active);  /* checkmark if active */
+    device_map_[container] = input_devices_[i];
+  }
+
+  scroll_content()->SizeToPreferredSize();
+  scroller()->Layout();
+}
+
+void AudioDetailedView::OnViewClicked(views::View* sender) {
+  if (sender == footer()->content()) {
+    TransitionToDefaultView();
+  } else {
+    AudioDeviceMap::iterator iter = device_map_.find(sender);
+    if (iter == device_map_.end())
+      return;
+    chromeos::AudioDevice& device = iter->second;
+    CrasAudioHandler::Get()->SwitchToDevice(device);
+  }
+}
+
+}  // namespace tray
+}  // namespace internal
+}  // namespace ash
diff --git a/ash/system/chromeos/audio/audio_detailed_view.h b/ash/system/chromeos/audio/audio_detailed_view.h
new file mode 100644
index 0000000..6953676
--- /dev/null
+++ b/ash/system/chromeos/audio/audio_detailed_view.h
@@ -0,0 +1,66 @@
+// 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_CHROMEOS_AUDIO_AUDIO_DETAILED_VIEW_H_
+#define ASH_SYSTEM_CHROMEOS_AUDIO_AUDIO_DETAILED_VIEW_H_
+
+#include "ash/system/tray/tray_details_view.h"
+#include "ash/system/tray/view_click_listener.h"
+#include "ash/system/user/login_status.h"
+#include "chromeos/audio/audio_device.h"
+
+#include "ui/gfx/font.h"
+
+namespace views {
+class View;
+}
+
+namespace ash {
+namespace internal {
+
+class HoverHighlightView;
+
+namespace tray {
+
+class AudioDetailedView : public TrayDetailsView,
+                          public ViewClickListener {
+ public:
+  AudioDetailedView(SystemTrayItem* owner, user::LoginStatus login);
+
+  virtual ~AudioDetailedView();
+
+  void Update();
+
+ private:
+  void AddScrollListInfoItem(const base::string16& text);
+
+  HoverHighlightView* AddScrollListItem(const base::string16& text,
+                                        gfx::Font::FontStyle style,
+                                        bool checked);
+
+  void CreateHeaderEntry();
+  void CreateItems();
+
+  void UpdateScrollableList();
+  void UpdateAudioDevices();
+
+  // Overridden from ViewClickListener.
+  virtual void OnViewClicked(views::View* sender) OVERRIDE;
+
+  user::LoginStatus login_;
+
+  typedef std::map<views::View*, chromeos::AudioDevice> AudioDeviceMap;
+
+  chromeos::AudioDeviceList output_devices_;
+  chromeos::AudioDeviceList input_devices_;
+  AudioDeviceMap device_map_;
+
+  DISALLOW_COPY_AND_ASSIGN(AudioDetailedView);
+};
+
+}  // namespace tray
+}  // namespace internal
+}  // namespace ash
+
+#endif  // ASH_SYSTEM_CHROMEOS_AUDIO_AUDIO_DETAILED_VIEW_H_
diff --git a/ash/system/chromeos/audio/tray_audio.cc b/ash/system/chromeos/audio/tray_audio.cc
deleted file mode 100644
index c1721f6..0000000
--- a/ash/system/chromeos/audio/tray_audio.cc
+++ /dev/null
@@ -1,663 +0,0 @@
-// Copyright (c) 2012 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.
-
-#include "ash/system/chromeos/audio/tray_audio.h"
-
-#include <cmath>
-
-#include "ash/ash_constants.h"
-#include "ash/ash_switches.h"
-#include "ash/metrics/user_metrics_recorder.h"
-#include "ash/shell.h"
-#include "ash/system/tray/actionable_view.h"
-#include "ash/system/tray/fixed_sized_scroll_view.h"
-#include "ash/system/tray/hover_highlight_view.h"
-#include "ash/system/tray/system_tray.h"
-#include "ash/system/tray/system_tray_delegate.h"
-#include "ash/system/tray/system_tray_notifier.h"
-#include "ash/system/tray/tray_constants.h"
-#include "ash/volume_control_delegate.h"
-#include "base/strings/utf_string_conversions.h"
-#include "chromeos/audio/cras_audio_handler.h"
-#include "grit/ash_resources.h"
-#include "grit/ash_strings.h"
-#include "third_party/skia/include/core/SkCanvas.h"
-#include "third_party/skia/include/core/SkPaint.h"
-#include "third_party/skia/include/core/SkRect.h"
-#include "third_party/skia/include/effects/SkGradientShader.h"
-#include "ui/base/l10n/l10n_util.h"
-#include "ui/base/resource/resource_bundle.h"
-#include "ui/gfx/canvas.h"
-#include "ui/gfx/font_list.h"
-#include "ui/gfx/image/image.h"
-#include "ui/gfx/image/image_skia_operations.h"
-#include "ui/views/controls/button/image_button.h"
-#include "ui/views/controls/image_view.h"
-#include "ui/views/controls/label.h"
-#include "ui/views/controls/slider.h"
-#include "ui/views/layout/box_layout.h"
-#include "ui/views/view.h"
-
-using chromeos::CrasAudioHandler;
-
-namespace ash {
-namespace internal {
-
-namespace {
-const int kVolumeImageWidth = 25;
-const int kVolumeImageHeight = 25;
-const int kBarSeparatorWidth = 25;
-const int kBarSeparatorHeight = 30;
-const int kSliderRightPaddingToVolumeViewEdge = 17;
-const int kExtraPaddingBetweenBarAndMore = 10;
-
-const int kNoAudioDeviceIcon = -1;
-
-// IDR_AURA_UBER_TRAY_VOLUME_LEVELS contains 5 images,
-// The one for mute is at the 0 index and the other
-// four are used for ascending volume levels.
-const int kVolumeLevels = 4;
-
-bool IsAudioMuted() {
-  return CrasAudioHandler::Get()->IsOutputMuted();
-}
-
-float GetVolumeLevel() {
-  return CrasAudioHandler::Get()->GetOutputVolumePercent() / 100.0f;
-}
-
-int GetAudioDeviceIconId(chromeos::AudioDeviceType type) {
-  if (type == chromeos::AUDIO_TYPE_HEADPHONE)
-    return IDR_AURA_UBER_TRAY_AUDIO_HEADPHONE;
-  else if (type == chromeos::AUDIO_TYPE_USB)
-    return IDR_AURA_UBER_TRAY_AUDIO_USB;
-  else if (type == chromeos::AUDIO_TYPE_BLUETOOTH)
-    return IDR_AURA_UBER_TRAY_AUDIO_BLUETOOTH;
-  else if (type == chromeos::AUDIO_TYPE_HDMI)
-    return IDR_AURA_UBER_TRAY_AUDIO_HDMI;
-  else
-    return kNoAudioDeviceIcon;
-}
-
-base::string16 GetAudioDeviceName(const chromeos::AudioDevice& device) {
-  switch(device.type) {
-    case chromeos::AUDIO_TYPE_HEADPHONE:
-      return l10n_util::GetStringUTF16(IDS_ASH_STATUS_TRAY_AUDIO_HEADPHONE);
-    case chromeos::AUDIO_TYPE_INTERNAL_SPEAKER:
-      return l10n_util::GetStringUTF16(
-          IDS_ASH_STATUS_TRAY_AUDIO_INTERNAL_SPEAKER);
-    case chromeos::AUDIO_TYPE_INTERNAL_MIC:
-      return l10n_util::GetStringUTF16(IDS_ASH_STATUS_TRAY_AUDIO_INTERNAL_MIC);
-    case chromeos::AUDIO_TYPE_USB:
-      return l10n_util::GetStringFUTF16(
-          IDS_ASH_STATUS_TRAY_AUDIO_USB_DEVICE,
-          base::UTF8ToUTF16(device.display_name));
-    case chromeos::AUDIO_TYPE_BLUETOOTH:
-      return l10n_util::GetStringFUTF16(
-          IDS_ASH_STATUS_TRAY_AUDIO_BLUETOOTH_DEVICE,
-          base::UTF8ToUTF16(device.display_name));
-    case chromeos::AUDIO_TYPE_HDMI:
-      return l10n_util::GetStringFUTF16(
-          IDS_ASH_STATUS_TRAY_AUDIO_HDMI_DEVICE,
-          base::UTF8ToUTF16(device.display_name));
-    default:
-      return base::UTF8ToUTF16(device.display_name);
-  }
-}
-
-}  // namespace
-
-namespace tray {
-
-class VolumeButton : public views::ToggleImageButton {
- public:
-  explicit VolumeButton(views::ButtonListener* listener)
-      : views::ToggleImageButton(listener),
-        image_index_(-1) {
-    SetImageAlignment(ALIGN_CENTER, ALIGN_MIDDLE);
-    image_ = ui::ResourceBundle::GetSharedInstance().GetImageNamed(
-        IDR_AURA_UBER_TRAY_VOLUME_LEVELS);
-    SetPreferredSize(gfx::Size(kTrayPopupItemHeight, kTrayPopupItemHeight));
-    Update();
-  }
-
-  virtual ~VolumeButton() {}
-
-  void Update() {
-    float level = GetVolumeLevel();
-    int image_index = IsAudioMuted() ?
-        0 : (level == 1.0 ?
-             kVolumeLevels :
-             std::max(1, int(std::ceil(level * (kVolumeLevels - 1)))));
-    if (image_index != image_index_) {
-      gfx::Rect region(0, image_index * kVolumeImageHeight,
-                       kVolumeImageWidth, kVolumeImageHeight);
-      gfx::ImageSkia image_skia = gfx::ImageSkiaOperations::ExtractSubset(
-          *(image_.ToImageSkia()), region);
-      SetImage(views::CustomButton::STATE_NORMAL, &image_skia);
-      image_index_ = image_index;
-    }
-    SchedulePaint();
-  }
-
- private:
-  // Overridden from views::View.
-  virtual gfx::Size GetPreferredSize() OVERRIDE {
-    gfx::Size size = views::ToggleImageButton::GetPreferredSize();
-    size.set_height(kTrayPopupItemHeight);
-    return size;
-  }
-
-  gfx::Image image_;
-  int image_index_;
-
-  DISALLOW_COPY_AND_ASSIGN(VolumeButton);
-};
-
-class VolumeSlider : public views::Slider {
- public:
-  explicit VolumeSlider(views::SliderListener* listener)
-      : views::Slider(listener, views::Slider::HORIZONTAL) {
-    set_focus_border_color(kFocusBorderColor);
-    SetValue(GetVolumeLevel());
-    SetAccessibleName(
-            ui::ResourceBundle::GetSharedInstance().GetLocalizedString(
-                IDS_ASH_STATUS_TRAY_VOLUME));
-    Update();
-  }
-  virtual ~VolumeSlider() {}
-
-  void Update() {
-    UpdateState(!IsAudioMuted());
-  }
-
-  DISALLOW_COPY_AND_ASSIGN(VolumeSlider);
-};
-
-// Vertical bar separator that can be placed on the VolumeView.
-class BarSeparator : public views::View {
- public:
-  BarSeparator() {}
-  virtual ~BarSeparator() {}
-
-  // Overriden from views::View.
-  virtual gfx::Size GetPreferredSize() OVERRIDE {
-    return gfx::Size(kBarSeparatorWidth, kBarSeparatorHeight);
-  }
-
- private:
-  virtual void OnPaint(gfx::Canvas* canvas) OVERRIDE {
-    canvas->FillRect(gfx::Rect(width() / 2, 0, 1, height()),
-                     kButtonStrokeColor);
-  }
-
-  DISALLOW_COPY_AND_ASSIGN(BarSeparator);
-};
-
-class VolumeView : public ActionableView,
-                   public views::ButtonListener,
-                   public views::SliderListener {
- public:
-  VolumeView(SystemTrayItem* owner, bool is_default_view)
-      : owner_(owner),
-        icon_(NULL),
-        slider_(NULL),
-        bar_(NULL),
-        device_type_(NULL),
-        more_(NULL),
-        is_default_view_(is_default_view) {
-    SetFocusable(false);
-    SetLayoutManager(new views::BoxLayout(views::BoxLayout::kHorizontal,
-          kTrayPopupPaddingHorizontal, 0, kTrayPopupPaddingBetweenItems));
-
-    icon_ = new VolumeButton(this);
-    AddChildView(icon_);
-
-    slider_ = new VolumeSlider(this);
-    AddChildView(slider_);
-
-    bar_ = new BarSeparator;
-    AddChildView(bar_);
-
-    device_type_ = new views::ImageView;
-    AddChildView(device_type_);
-
-    more_ = new views::ImageView;
-    more_->EnableCanvasFlippingForRTLUI(true);
-    more_->SetImage(ui::ResourceBundle::GetSharedInstance().GetImageNamed(
-        IDR_AURA_UBER_TRAY_MORE).ToImageSkia());
-    AddChildView(more_);
-
-    Update();
-  }
-
-  virtual ~VolumeView() {}
-
-  void Update() {
-    icon_->Update();
-    slider_->Update();
-    UpdateDeviceTypeAndMore();
-    Layout();
-  }
-
-  // Sets volume level on slider_, |percent| is ranged from [0.00] to [1.00].
-  void SetVolumeLevel(float percent) {
-    // Slider's value is in finer granularity than audio volume level(0.01),
-    // there will be a small discrepancy between slider's value and volume level
-    // on audio side. To avoid the jittering in slider UI, do not set change
-    // slider value if the change is less than 1%.
-    if (std::abs(percent-slider_->value()) < 0.01)
-      return;
-    // The change in volume will be reflected via accessibility system events,
-    // so we prevent the UI event from being sent here.
-    slider_->set_enable_accessibility_events(false);
-    slider_->SetValue(percent);
-    // It is possible that the volume was (un)muted, but the actual volume level
-    // did not change. In that case, setting the value of the slider won't
-    // trigger an update. So explicitly trigger an update.
-    Update();
-    slider_->set_enable_accessibility_events(true);
-  }
-
- private:
-  // Updates bar_, device_type_ icon, and more_ buttons.
-  void UpdateDeviceTypeAndMore() {
-    if (!ash::switches::ShowAudioDeviceMenu() || !is_default_view_) {
-      more_->SetVisible(false);
-      bar_->SetVisible(false);
-      device_type_->SetVisible(false);
-      return;
-    }
-
-    CrasAudioHandler* audio_handler = CrasAudioHandler::Get();
-    bool show_more = audio_handler->has_alternative_output() ||
-                     audio_handler->has_alternative_input();
-    more_->SetVisible(show_more);
-
-    // Show output device icon if necessary.
-    chromeos::AudioDevice device;
-    if (!audio_handler->GetActiveOutputDevice(&device))
-      return;
-    int device_icon = GetAudioDeviceIconId(device.type);
-    bar_->SetVisible(show_more);
-    if (device_icon != kNoAudioDeviceIcon) {
-      device_type_->SetVisible(true);
-      device_type_->SetImage(
-          ui::ResourceBundle::GetSharedInstance().GetImageNamed(
-              device_icon).ToImageSkia());
-    } else {
-      device_type_->SetVisible(false);
-    }
-  }
-
-  void HandleVolumeUp(int volume) {
-    CrasAudioHandler* audio_handler = CrasAudioHandler::Get();
-    audio_handler->SetOutputVolumePercent(volume);
-    if (audio_handler->IsOutputMuted() &&
-        !audio_handler->IsOutputVolumeBelowDefaultMuteLvel())
-      audio_handler->SetOutputMute(false);
-  }
-
-  void HandleVolumeDown(int volume) {
-    CrasAudioHandler* audio_handler =  CrasAudioHandler::Get();
-    audio_handler->SetOutputVolumePercent(volume);
-    if (audio_handler->IsOutputVolumeBelowDefaultMuteLvel() &&
-        !audio_handler->IsOutputMuted()) {
-      audio_handler->SetOutputMute(true);
-    } else if (!audio_handler->IsOutputVolumeBelowDefaultMuteLvel() &&
-               audio_handler->IsOutputMuted()) {
-      audio_handler->SetOutputMute(false);
-    }
-  }
-
-  // Overridden from views::View.
-  virtual void Layout() OVERRIDE {
-    views::View::Layout();
-
-    if (!more_->visible()) {
-      int w = width() - slider_->bounds().x() -
-              kSliderRightPaddingToVolumeViewEdge;
-      slider_->SetSize(gfx::Size(w, slider_->height()));
-      return;
-    }
-
-    // Make sure the chevron always has the full size.
-    gfx::Size size = more_->GetPreferredSize();
-    gfx::Rect bounds(size);
-    bounds.set_x(width() - size.width() - kTrayPopupPaddingBetweenItems);
-    bounds.set_y((height() - size.height()) / 2);
-    more_->SetBoundsRect(bounds);
-
-    // Layout either bar_ or device_type_ at the left of the more_ button.
-    views::View* view_left_to_more;
-    if (device_type_->visible())
-      view_left_to_more = device_type_;
-    else
-      view_left_to_more = bar_;
-    gfx::Size view_size = view_left_to_more->GetPreferredSize();
-    gfx::Rect view_bounds(view_size);
-    view_bounds.set_x(more_->bounds().x() - view_size.width() -
-                     kExtraPaddingBetweenBarAndMore);
-    view_bounds.set_y((height() - view_size.height()) / 2);
-    view_left_to_more->SetBoundsRect(view_bounds);
-
-    // Layout vertical bar next to view_left_to_more if device_type_ is visible.
-    if (device_type_->visible()) {
-      gfx::Size bar_size = bar_->GetPreferredSize();
-      gfx::Rect bar_bounds(bar_size);
-      bar_bounds.set_x(view_left_to_more->bounds().x() - bar_size.width());
-      bar_bounds.set_y((height() - bar_size.height()) / 2);
-      bar_->SetBoundsRect(bar_bounds);
-    }
-
-    // Layout slider, calculate slider width.
-    gfx::Rect slider_bounds = slider_->bounds();
-    slider_bounds.set_width(
-        bar_->bounds().x()
-        - (device_type_->visible() ? 0 : kTrayPopupPaddingBetweenItems)
-        - slider_bounds.x());
-    slider_->SetBoundsRect(slider_bounds);
-  }
-
-  // Overridden from views::ButtonListener.
-  virtual void ButtonPressed(views::Button* sender,
-                             const ui::Event& event) OVERRIDE {
-    CHECK(sender == icon_);
-    bool mute_on = !IsAudioMuted();
-    CrasAudioHandler::Get()->SetOutputMute(mute_on);
-    if (!mute_on)
-      CrasAudioHandler::Get()->AdjustOutputVolumeToAudibleLevel();
-  }
-
-  // Overridden from views:SliderListener.
-  virtual void SliderValueChanged(views::Slider* sender,
-                                  float value,
-                                  float old_value,
-                                  views::SliderChangeReason reason) OVERRIDE {
-    if (reason == views::VALUE_CHANGED_BY_USER) {
-      int volume = value * 100.0f;
-      int old_volume = CrasAudioHandler::Get()->GetOutputVolumePercent();
-      // Do not call change audio volume if the difference is less than
-      // 1%, which is beyond cras audio api's granularity for output volume.
-      if (std::abs(volume - old_volume) < 1)
-        return;
-      Shell::GetInstance()->metrics()->RecordUserMetricsAction(
-          is_default_view_ ?
-          ash::UMA_STATUS_AREA_CHANGED_VOLUME_MENU :
-          ash::UMA_STATUS_AREA_CHANGED_VOLUME_POPUP);
-      if (volume > old_volume)
-        HandleVolumeUp(volume);
-      else
-        HandleVolumeDown(volume);
-    }
-    icon_->Update();
-  }
-
-  // Overriden from ActionableView.
-  virtual bool PerformAction(const ui::Event& event) OVERRIDE {
-    if (!more_->visible())
-      return false;
-    owner_->TransitionDetailedView();
-    return true;
-  }
-
-  SystemTrayItem* owner_;
-  VolumeButton* icon_;
-  VolumeSlider* slider_;
-  BarSeparator* bar_;
-  views::ImageView* device_type_;
-  views::ImageView* more_;
-  bool is_default_view_;
-
-  DISALLOW_COPY_AND_ASSIGN(VolumeView);
-};
-
-class AudioDetailedView : public TrayDetailsView,
-                          public ViewClickListener {
- public:
-  AudioDetailedView(SystemTrayItem* owner, user::LoginStatus login)
-      : TrayDetailsView(owner),
-        login_(login) {
-    CreateItems();
-    Update();
-  }
-
-  virtual ~AudioDetailedView() {
-  }
-
-  void Update() {
-    UpdateAudioDevices();
-    Layout();
-  }
-
- private:
-  void CreateItems() {
-    CreateScrollableList();
-    CreateHeaderEntry();
-  }
-
-  void CreateHeaderEntry() {
-    CreateSpecialRow(IDS_ASH_STATUS_TRAY_AUDIO, this);
-  }
-
-  void UpdateAudioDevices() {
-    output_devices_.clear();
-    input_devices_.clear();
-    chromeos::AudioDeviceList devices;
-    CrasAudioHandler::Get()->GetAudioDevices(&devices);
-    for (size_t i = 0; i < devices.size(); ++i) {
-      if (devices[i].is_input)
-        input_devices_.push_back(devices[i]);
-      else
-        output_devices_.push_back(devices[i]);
-    }
-    UpdateScrollableList();
-  }
-
-  void UpdateScrollableList() {
-    scroll_content()->RemoveAllChildViews(true);
-    device_map_.clear();
-
-    // Add audio output devices.
-    AddScrollListInfoItem(
-        l10n_util::GetStringUTF16(IDS_ASH_STATUS_TRAY_AUDIO_OUTPUT));
-    for (size_t i = 0; i < output_devices_.size(); ++i) {
-      HoverHighlightView* container = AddScrollListItem(
-          GetAudioDeviceName(output_devices_[i]),
-          gfx::Font::NORMAL,
-          output_devices_[i].active);  /* checkmark if active */
-      device_map_[container] = output_devices_[i];
-    }
-
-    AddScrollSeparator();
-
-    // Add audio input devices.
-    AddScrollListInfoItem(
-        l10n_util::GetStringUTF16(IDS_ASH_STATUS_TRAY_AUDIO_INPUT));
-    for (size_t i = 0; i < input_devices_.size(); ++i) {
-      HoverHighlightView* container = AddScrollListItem(
-          GetAudioDeviceName(input_devices_[i]),
-          gfx::Font::NORMAL,
-          input_devices_[i].active);  /* checkmark if active */
-      device_map_[container] = input_devices_[i];
-    }
-
-    scroll_content()->SizeToPreferredSize();
-    scroller()->Layout();
-  }
-
-  void AddScrollListInfoItem(const base::string16& text) {
-    views::Label* label = new views::Label(
-        text,
-        ui::ResourceBundle::GetSharedInstance().GetFontList(
-            ui::ResourceBundle::BoldFont));
-
-    //  Align info item with checkbox items
-    int margin = kTrayPopupPaddingHorizontal +
-        kTrayPopupDetailsLabelExtraLeftMargin;
-    int left_margin = 0;
-    int right_margin = 0;
-    if (base::i18n::IsRTL())
-      right_margin = margin;
-    else
-      left_margin = margin;
-
-    label->SetBorder(
-        views::Border::CreateEmptyBorder(ash::kTrayPopupPaddingBetweenItems,
-                                         left_margin,
-                                         ash::kTrayPopupPaddingBetweenItems,
-                                         right_margin));
-    label->SetHorizontalAlignment(gfx::ALIGN_LEFT);
-    label->SetEnabledColor(SkColorSetARGB(192, 0, 0, 0));
-
-    scroll_content()->AddChildView(label);
-  }
-
-  HoverHighlightView* AddScrollListItem(const base::string16& text,
-                                        gfx::Font::FontStyle style,
-                                        bool checked) {
-    HoverHighlightView* container = new HoverHighlightView(this);
-    container->AddCheckableLabel(text, style, checked);
-    scroll_content()->AddChildView(container);
-    return container;
-  }
-
-  // Overridden from ViewClickListener.
-  virtual void OnViewClicked(views::View* sender) OVERRIDE {
-    if (sender == footer()->content()) {
-      TransitionToDefaultView();
-    } else {
-      AudioDeviceMap::iterator iter = device_map_.find(sender);
-      if (iter == device_map_.end())
-        return;
-      chromeos::AudioDevice& device = iter->second;
-      CrasAudioHandler::Get()->SwitchToDevice(device);
-    }
-  }
-
-  typedef std::map<views::View*, chromeos::AudioDevice> AudioDeviceMap;
-
-  user::LoginStatus login_;
-  chromeos::AudioDeviceList output_devices_;
-  chromeos::AudioDeviceList input_devices_;
-  AudioDeviceMap device_map_;
-
-  DISALLOW_COPY_AND_ASSIGN(AudioDetailedView);
-};
-
-}  // namespace tray
-
-TrayAudio::TrayAudio(SystemTray* system_tray)
-    : TrayImageItem(system_tray, IDR_AURA_UBER_TRAY_VOLUME_MUTE),
-      volume_view_(NULL),
-      audio_detail_(NULL),
-      pop_up_volume_view_(false) {
-  CrasAudioHandler::Get()->AddAudioObserver(this);
-}
-
-TrayAudio::~TrayAudio() {
-  if (CrasAudioHandler::IsInitialized())
-    CrasAudioHandler::Get()->RemoveAudioObserver(this);
-}
-
-bool TrayAudio::GetInitialVisibility() {
-  return IsAudioMuted();
-}
-
-views::View* TrayAudio::CreateDefaultView(user::LoginStatus status) {
-  volume_view_ = new tray::VolumeView(this, true);
-  return volume_view_;
-}
-
-views::View* TrayAudio::CreateDetailedView(user::LoginStatus status) {
-  if (!ash::switches::ShowAudioDeviceMenu() || pop_up_volume_view_) {
-    volume_view_ = new tray::VolumeView(this, false);
-    return volume_view_;
-  } else {
-    Shell::GetInstance()->metrics()->RecordUserMetricsAction(
-        ash::UMA_STATUS_AREA_DETAILED_AUDIO_VIEW);
-    audio_detail_ = new tray::AudioDetailedView(this, status);
-    return audio_detail_;
-  }
-}
-
-void TrayAudio::DestroyDefaultView() {
-  volume_view_ = NULL;
-}
-
-void TrayAudio::DestroyDetailedView() {
-  if (audio_detail_) {
-    audio_detail_ = NULL;
-  } else if (volume_view_) {
-    volume_view_ = NULL;
-    pop_up_volume_view_ = false;
-  }
-}
-
-bool TrayAudio::ShouldHideArrow() const {
-  return true;
-}
-
-bool TrayAudio::ShouldShowShelf() const {
-  return ash::switches::ShowAudioDeviceMenu() && !pop_up_volume_view_;
-}
-
-void TrayAudio::OnOutputVolumeChanged() {
-  float percent = GetVolumeLevel();
-  if (tray_view())
-    tray_view()->SetVisible(GetInitialVisibility());
-
-  if (volume_view_) {
-    volume_view_->SetVolumeLevel(percent);
-    SetDetailedViewCloseDelay(kTrayPopupAutoCloseDelayInSeconds);
-    return;
-  }
-  pop_up_volume_view_ = true;
-  PopupDetailedView(kTrayPopupAutoCloseDelayInSeconds, false);
-}
-
-void TrayAudio::OnOutputMuteChanged() {
-  if (tray_view())
-      tray_view()->SetVisible(GetInitialVisibility());
-
-  if (volume_view_) {
-    volume_view_->Update();
-    SetDetailedViewCloseDelay(kTrayPopupAutoCloseDelayInSeconds);
-  } else {
-    pop_up_volume_view_ = true;
-    PopupDetailedView(kTrayPopupAutoCloseDelayInSeconds, false);
-  }
-}
-
-void TrayAudio::OnInputGainChanged() {
-}
-
-void TrayAudio::OnInputMuteChanged() {
-}
-
-void TrayAudio::OnAudioNodesChanged() {
-  Update();
-}
-
-void TrayAudio::OnActiveOutputNodeChanged() {
-  Update();
-}
-
-void TrayAudio::OnActiveInputNodeChanged() {
-  Update();
-}
-
-void TrayAudio::Update() {
-  if (tray_view())
-      tray_view()->SetVisible(GetInitialVisibility());
-  if (audio_detail_)
-    audio_detail_->Update();
-  if (volume_view_) {
-    volume_view_->SetVolumeLevel(GetVolumeLevel());
-    volume_view_->Update();
-  }
-}
-
-}  // namespace internal
-}  // namespace ash
diff --git a/ash/system/chromeos/audio/tray_audio_chromeos.cc b/ash/system/chromeos/audio/tray_audio_chromeos.cc
new file mode 100644
index 0000000..f80d712
--- /dev/null
+++ b/ash/system/chromeos/audio/tray_audio_chromeos.cc
@@ -0,0 +1,61 @@
+// 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.
+
+#include "ash/system/chromeos/audio/tray_audio_chromeos.h"
+
+#include "ash/ash_switches.h"
+#include "ash/metrics/user_metrics_recorder.h"
+#include "ash/shell.h"
+#include "ash/system/audio/volume_view.h"
+#include "ash/system/chromeos/audio/audio_detailed_view.h"
+#include "ash/system/chromeos/audio/tray_audio_delegate_chromeos.h"
+#include "ui/views/view.h"
+
+namespace ash {
+
+using system::TrayAudioDelegate;
+using system::TrayAudioDelegateChromeOs;
+
+namespace internal {
+
+TrayAudioChromeOs::TrayAudioChromeOs(SystemTray* system_tray)
+    : TrayAudio(system_tray,
+                scoped_ptr<TrayAudioDelegate>(new TrayAudioDelegateChromeOs())),
+      audio_detail_view_(NULL) {
+}
+
+TrayAudioChromeOs::~TrayAudioChromeOs() {
+}
+
+void TrayAudioChromeOs::Update() {
+  TrayAudio::Update();
+
+  if (audio_detail_view_)
+    audio_detail_view_->Update();
+}
+
+views::View* TrayAudioChromeOs::CreateDetailedView(user::LoginStatus status) {
+  if (!ash::switches::ShowAudioDeviceMenu() || pop_up_volume_view_) {
+    volume_view_ = new tray::VolumeView(this, audio_delegate_.get(), false);
+    return volume_view_;
+  } else {
+    Shell::GetInstance()->metrics()->RecordUserMetricsAction(
+        ash::UMA_STATUS_AREA_DETAILED_AUDIO_VIEW);
+    audio_detail_view_ =
+        new tray::AudioDetailedView(this, status);
+    return audio_detail_view_;
+  }
+}
+
+void TrayAudioChromeOs::DestroyDetailedView() {
+  if (audio_detail_view_) {
+    audio_detail_view_ = NULL;
+  } else if (volume_view_) {
+    volume_view_ = NULL;
+    pop_up_volume_view_ = false;
+  }
+}
+
+}  // namespace internal
+}  // namespace ash
diff --git a/ash/system/chromeos/audio/tray_audio_chromeos.h b/ash/system/chromeos/audio/tray_audio_chromeos.h
new file mode 100644
index 0000000..6817f85
--- /dev/null
+++ b/ash/system/chromeos/audio/tray_audio_chromeos.h
@@ -0,0 +1,42 @@
+// 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_CHROMEOS_AUDIO_TRAY_AUDIO_CHROMEOS_H_
+#define ASH_SYSTEM_CHROMEOS_AUDIO_TRAY_AUDIO_CHROMEOS_H_
+
+#include "ash/ash_export.h"
+#include "ash/system/audio/tray_audio.h"
+#include "base/memory/scoped_ptr.h"
+
+namespace ash {
+
+namespace internal {
+
+namespace tray {
+class AudioDetailedView;
+}
+
+class ASH_EXPORT TrayAudioChromeOs : public TrayAudio {
+ public:
+  explicit TrayAudioChromeOs(SystemTray* system_tray);
+  virtual ~TrayAudioChromeOs();
+
+ protected:
+  // Overridden from TrayAudio
+  virtual void Update() OVERRIDE;
+
+ private:
+  // Overridden from SystemTrayItem.
+  virtual views::View* CreateDetailedView(user::LoginStatus status) OVERRIDE;
+  virtual void DestroyDetailedView() OVERRIDE;
+
+  tray::AudioDetailedView* audio_detail_view_;
+
+  DISALLOW_COPY_AND_ASSIGN(TrayAudioChromeOs);
+};
+
+}  // namespace internal
+}  // namespace ash
+
+#endif  // ASH_SYSTEM_CHROMEOS_AUDIO_TRAY_AUDIO_CHROMEOS_H_
diff --git a/ash/system/chromeos/audio/tray_audio_delegate_chromeos.cc b/ash/system/chromeos/audio/tray_audio_delegate_chromeos.cc
new file mode 100644
index 0000000..59f6ecf
--- /dev/null
+++ b/ash/system/chromeos/audio/tray_audio_delegate_chromeos.cc
@@ -0,0 +1,65 @@
+// 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.
+
+#include "ash/system/chromeos/audio/tray_audio_delegate_chromeos.h"
+
+#include "chromeos/audio/cras_audio_handler.h"
+#include "grit/ash_resources.h"
+#include "grit/ash_strings.h"
+
+using chromeos::CrasAudioHandler;
+
+namespace ash  {
+namespace system {
+
+void TrayAudioDelegateChromeOs::AdjustOutputVolumeToAudibleLevel() {
+  CrasAudioHandler::Get()->AdjustOutputVolumeToAudibleLevel();
+}
+
+int TrayAudioDelegateChromeOs::GetOutputDefaultVolumeMuteLevel() {
+  return CrasAudioHandler::Get()->GetOutputDefaultVolumeMuteThreshold();
+}
+
+int TrayAudioDelegateChromeOs::GetOutputVolumeLevel() {
+  return CrasAudioHandler::Get()->GetOutputVolumePercent();
+}
+
+int TrayAudioDelegateChromeOs::GetActiveOutputDeviceIconId() {
+  chromeos::AudioDevice device;
+  if (!CrasAudioHandler::Get()->GetActiveOutputDevice(&device))
+    return kNoAudioDeviceIcon;
+
+  if (device.type == chromeos::AUDIO_TYPE_HEADPHONE)
+    return IDR_AURA_UBER_TRAY_AUDIO_HEADPHONE;
+  else if (device.type == chromeos::AUDIO_TYPE_USB)
+    return IDR_AURA_UBER_TRAY_AUDIO_USB;
+  else if (device.type == chromeos::AUDIO_TYPE_BLUETOOTH)
+    return IDR_AURA_UBER_TRAY_AUDIO_BLUETOOTH;
+  else if (device.type == chromeos::AUDIO_TYPE_HDMI)
+    return IDR_AURA_UBER_TRAY_AUDIO_HDMI;
+  else
+    return kNoAudioDeviceIcon;
+}
+
+
+bool TrayAudioDelegateChromeOs::HasAlternativeSources() {
+  CrasAudioHandler* audio_handler = CrasAudioHandler::Get();
+  return (audio_handler->has_alternative_output() ||
+          audio_handler->has_alternative_input());
+}
+
+bool TrayAudioDelegateChromeOs::IsOutputAudioMuted() {
+  return CrasAudioHandler::Get()->IsOutputMuted();
+}
+
+void TrayAudioDelegateChromeOs::SetOutputAudioIsMuted(bool is_muted) {
+  CrasAudioHandler::Get()->SetOutputMute(is_muted);
+}
+
+void TrayAudioDelegateChromeOs::SetOutputVolumeLevel(int level) {
+  CrasAudioHandler::Get()->SetOutputVolumePercent(level);
+}
+
+}  // namespace system
+}  // namespace ash
diff --git a/ash/system/chromeos/audio/tray_audio_delegate_chromeos.h b/ash/system/chromeos/audio/tray_audio_delegate_chromeos.h
new file mode 100644
index 0000000..58e714d
--- /dev/null
+++ b/ash/system/chromeos/audio/tray_audio_delegate_chromeos.h
@@ -0,0 +1,33 @@
+// 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_TRAY_AUDIO_DELEGATE_CHROMEOS_H_
+#define ASH_SYSTEM_AUDIO_TRAY_AUDIO_DELEGATE_CHROMEOS_H_
+
+#include "ash/ash_export.h"
+#include "ash/system/audio/tray_audio_delegate.h"
+#include "base/compiler_specific.h"
+
+namespace ash {
+namespace system {
+
+class ASH_EXPORT TrayAudioDelegateChromeOs : public TrayAudioDelegate {
+ public:
+  virtual ~TrayAudioDelegateChromeOs() {}
+
+  // Overridden from TrayAudioDelegate.
+  virtual void AdjustOutputVolumeToAudibleLevel() OVERRIDE;
+  virtual int GetOutputDefaultVolumeMuteLevel() OVERRIDE;
+  virtual int GetOutputVolumeLevel() OVERRIDE;
+  virtual int GetActiveOutputDeviceIconId() OVERRIDE;
+  virtual bool HasAlternativeSources() OVERRIDE;
+  virtual bool IsOutputAudioMuted() OVERRIDE;
+  virtual void SetOutputAudioIsMuted(bool is_muted) OVERRIDE;
+  virtual void SetOutputVolumeLevel(int level) OVERRIDE;
+};
+
+}  // namespace system
+}  // namespace ash
+
+#endif  // ASH_SYSTEM_AUDIO_TRAY_AUDIO_DELEGATE_CHROMEOS_H_
diff --git a/ash/system/tray/system_tray.cc b/ash/system/tray/system_tray.cc
index 942b15c..7b34dee 100644
--- a/ash/system/tray/system_tray.cc
+++ b/ash/system/tray/system_tray.cc
@@ -10,6 +10,7 @@
 #include "ash/shell.h"
 #include "ash/shell/panel_window.h"
 #include "ash/shell_window_ids.h"
+#include "ash/system/audio/tray_audio.h"
 #include "ash/system/bluetooth/tray_bluetooth.h"
 #include "ash/system/date/tray_date.h"
 #include "ash/system/drive/tray_drive.h"
@@ -47,7 +48,7 @@
 #include "ui/views/view.h"
 
 #if defined(OS_CHROMEOS)
-#include "ash/system/chromeos/audio/tray_audio.h"
+#include "ash/system/chromeos/audio/tray_audio_chromeos.h"
 #include "ash/system/chromeos/brightness/tray_brightness.h"
 #include "ash/system/chromeos/enterprise/tray_enterprise.h"
 #include "ash/system/chromeos/managed/tray_locally_managed_user.h"
@@ -195,7 +196,7 @@ void SystemTray::CreateItems(SystemTrayDelegate* delegate) {
   AddTrayItem(new internal::TrayDisplay(this));
   AddTrayItem(new internal::ScreenCaptureTrayItem(this));
   AddTrayItem(new internal::ScreenShareTrayItem(this));
-  AddTrayItem(new internal::TrayAudio(this));
+  AddTrayItem(new internal::TrayAudioChromeOs(this));
   AddTrayItem(new internal::TrayBrightness(this));
   AddTrayItem(new internal::TrayCapsLock(this));
   AddTrayItem(new internal::TraySettings(this));
diff --git a/ash/system/tray/system_tray_notifier.cc b/ash/system/tray/system_tray_notifier.cc
index 95b6789..6a2cc79 100644
--- a/ash/system/tray/system_tray_notifier.cc
+++ b/ash/system/tray/system_tray_notifier.cc
@@ -29,6 +29,14 @@ void SystemTrayNotifier::RemoveAccessibilityObserver(
   accessibility_observers_.RemoveObserver(observer);
 }
 
+void SystemTrayNotifier::AddAudioObserver(AudioObserver* observer) {
+  audio_observers_.AddObserver(observer);
+}
+
+void SystemTrayNotifier::RemoveAudioObserver(AudioObserver* observer) {
+  audio_observers_.RemoveObserver(observer);
+}
+
 void SystemTrayNotifier::AddBluetoothObserver(BluetoothObserver* observer) {
   bluetooth_observers_.AddObserver(observer);
 }
@@ -170,6 +178,41 @@ void SystemTrayNotifier::NotifyAccessibilityModeChanged(
       OnAccessibilityModeChanged(notify));
 }
 
+void SystemTrayNotifier::NotifyAudioOutputVolumeChanged() {
+  FOR_EACH_OBSERVER(
+      AudioObserver,
+      audio_observers_,
+      OnOutputVolumeChanged());
+}
+
+void SystemTrayNotifier::NotifyAudioOutputMuteChanged() {
+  FOR_EACH_OBSERVER(
+      AudioObserver,
+      audio_observers_,
+      OnOutputMuteChanged());
+}
+
+void SystemTrayNotifier::NotifyAudioNodesChanged() {
+  FOR_EACH_OBSERVER(
+      AudioObserver,
+      audio_observers_,
+      OnAudioNodesChanged());
+}
+
+void SystemTrayNotifier::NotifyAudioActiveOutputNodeChanged() {
+  FOR_EACH_OBSERVER(
+      AudioObserver,
+      audio_observers_,
+      OnActiveOutputNodeChanged());
+}
+
+void SystemTrayNotifier::NotifyAudioActiveInputNodeChanged() {
+  FOR_EACH_OBSERVER(
+      AudioObserver,
+      audio_observers_,
+      OnActiveInputNodeChanged());
+}
+
 void SystemTrayNotifier::NotifyTracingModeChanged(bool value) {
   FOR_EACH_OBSERVER(
       TracingObserver,
diff --git a/ash/system/tray/system_tray_notifier.h b/ash/system/tray/system_tray_notifier.h
index 6124040..bfd7ff0 100644
--- a/ash/system/tray/system_tray_notifier.h
+++ b/ash/system/tray/system_tray_notifier.h
@@ -9,6 +9,7 @@
 #include <vector>
 
 #include "ash/ash_export.h"
+#include "ash/system/audio/audio_observer.h"
 #include "ash/system/bluetooth/bluetooth_observer.h"
 #include "ash/system/chromeos/tray_tracing.h"
 #include "ash/system/date/clock_observer.h"
@@ -38,13 +39,16 @@ class NetworkStateNotifier;
 #endif
 
 class ASH_EXPORT SystemTrayNotifier {
-public:
+ public:
   SystemTrayNotifier();
   ~SystemTrayNotifier();
 
   void AddAccessibilityObserver(AccessibilityObserver* observer);
   void RemoveAccessibilityObserver(AccessibilityObserver* observer);
 
+  void AddAudioObserver(AudioObserver* observer);
+  void RemoveAudioObserver(AudioObserver* observer);
+
   void AddBluetoothObserver(BluetoothObserver* observer);
   void RemoveBluetoothObserver(BluetoothObserver* observer);
 
@@ -94,6 +98,11 @@ public:
 
   void NotifyAccessibilityModeChanged(
       AccessibilityNotificationVisibility notify);
+  void NotifyAudioOutputVolumeChanged();
+  void NotifyAudioOutputMuteChanged();
+  void NotifyAudioNodesChanged();
+  void NotifyAudioActiveOutputNodeChanged();
+  void NotifyAudioActiveInputNodeChanged();
   void NotifyTracingModeChanged(bool value);
   void NotifyRefreshBluetooth();
   void NotifyBluetoothDiscoveringChanged();
@@ -131,6 +140,7 @@ public:
 
  private:
   ObserverList<AccessibilityObserver> accessibility_observers_;
+  ObserverList<AudioObserver> audio_observers_;
   ObserverList<BluetoothObserver> bluetooth_observers_;
   ObserverList<CapsLockObserver> caps_lock_observers_;
   ObserverList<ClockObserver> clock_observers_;
diff --git a/chrome/browser/ui/ash/system_tray_delegate_chromeos.cc b/chrome/browser/ui/ash/system_tray_delegate_chromeos.cc
index 5b6ec0a..2c320e9 100644
--- a/chrome/browser/ui/ash/system_tray_delegate_chromeos.cc
+++ b/chrome/browser/ui/ash/system_tray_delegate_chromeos.cc
@@ -314,6 +314,9 @@ void SystemTrayDelegateChromeOS::Initialize() {
 
   if (LoginState::IsInitialized())
     LoginState::Get()->AddObserver(this);
+
+  if (CrasAudioHandler::IsInitialized())
+    CrasAudioHandler::Get()->AddAudioObserver(this);
 }
 
 void SystemTrayDelegateChromeOS::Shutdown() {
@@ -369,7 +372,10 @@ SystemTrayDelegateChromeOS::~SystemTrayDelegateChromeOS() {
       ->RemoveSessionStateObserver(this);
   LoginState::Get()->RemoveObserver(this);
 
-  // Stop observing Drive operations.
+  if (CrasAudioHandler::IsInitialized())
+    CrasAudioHandler::Get()->RemoveAudioObserver(this);
+
+// Stop observing Drive operations.
   UnobserveDriveUpdates();
 
   policy::BrowserPolicyConnectorChromeOS* connector =
@@ -1210,6 +1216,33 @@ void SystemTrayDelegateChromeOS::InputMethodMenuItemChanged(
   GetSystemTrayNotifier()->NotifyRefreshIME(false);
 }
 
+// Overridden from CrasAudioHandler::AudioObserver.
+void SystemTrayDelegateChromeOS::OnOutputVolumeChanged() {
+  GetSystemTrayNotifier()->NotifyAudioOutputVolumeChanged();
+}
+
+void SystemTrayDelegateChromeOS::OnOutputMuteChanged() {
+  GetSystemTrayNotifier()->NotifyAudioOutputMuteChanged();
+}
+
+void SystemTrayDelegateChromeOS::OnInputGainChanged() {
+}
+
+void SystemTrayDelegateChromeOS::OnInputMuteChanged() {
+}
+
+void SystemTrayDelegateChromeOS::OnAudioNodesChanged() {
+  GetSystemTrayNotifier()->NotifyAudioNodesChanged();
+}
+
+void SystemTrayDelegateChromeOS::OnActiveOutputNodeChanged() {
+  GetSystemTrayNotifier()->NotifyAudioActiveOutputNodeChanged();
+}
+
+void SystemTrayDelegateChromeOS::OnActiveInputNodeChanged() {
+  GetSystemTrayNotifier()->NotifyAudioActiveInputNodeChanged();
+}
+
 // drive::JobListObserver overrides.
 void SystemTrayDelegateChromeOS::OnJobAdded(const drive::JobInfo& job_info) {
   OnJobUpdated(job_info);
diff --git a/chrome/browser/ui/ash/system_tray_delegate_chromeos.h b/chrome/browser/ui/ash/system_tray_delegate_chromeos.h
index f465dd3..ec6fb22 100644
--- a/chrome/browser/ui/ash/system_tray_delegate_chromeos.h
+++ b/chrome/browser/ui/ash/system_tray_delegate_chromeos.h
@@ -20,6 +20,7 @@
 #include "chrome/browser/chromeos/events/system_key_event_listener.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/ash/system_tray_delegate_chromeos.h"
+#include "chromeos/audio/cras_audio_handler.h"
 #include "chromeos/dbus/session_manager_client.h"
 #include "chromeos/ime/input_method_manager.h"
 #include "chromeos/login/login_state.h"
@@ -38,6 +39,7 @@ class SystemTrayDelegateChromeOS
       public content::NotificationObserver,
       public input_method::InputMethodManager::Observer,
       public chromeos::LoginState::Observer,
+      public chromeos::CrasAudioHandler::AudioObserver,
       public device::BluetoothAdapter::Observer,
       public SystemKeyEventListener::CapsLockObserver,
       public policy::CloudPolicyStore::Observer,
@@ -186,6 +188,15 @@ class SystemTrayDelegateChromeOS
   virtual void InputMethodMenuItemChanged(
       ash::ime::InputMethodMenuManager* manager) OVERRIDE;
 
+  // Overridden from CrasAudioHandler::AudioObserver.
+  virtual void OnOutputVolumeChanged() OVERRIDE;
+  virtual void OnOutputMuteChanged() OVERRIDE;
+  virtual void OnInputGainChanged() OVERRIDE;
+  virtual void OnInputMuteChanged() OVERRIDE;
+  virtual void OnAudioNodesChanged() OVERRIDE;
+  virtual void OnActiveOutputNodeChanged() OVERRIDE;
+  virtual void OnActiveInputNodeChanged() OVERRIDE;
+
   // drive::JobListObserver overrides.
   virtual void OnJobAdded(const drive::JobInfo& job_info) OVERRIDE;
 
diff --git a/chromeos/audio/cras_audio_handler.cc b/chromeos/audio/cras_audio_handler.cc
index 0045f84..fd2d92e 100644
--- a/chromeos/audio/cras_audio_handler.cc
+++ b/chromeos/audio/cras_audio_handler.cc
@@ -130,6 +130,10 @@ bool CrasAudioHandler::IsInputMutedForDevice(uint64 device_id) {
   return audio_pref_handler_->GetMuteValue(*device);
 }
 
+int CrasAudioHandler::GetOutputDefaultVolumeMuteThreshold() {
+  return kMuteThresholdPercent;
+}
+
 int CrasAudioHandler::GetOutputVolumePercent() {
   return output_volume_;
 }
diff --git a/chromeos/audio/cras_audio_handler.h b/chromeos/audio/cras_audio_handler.h
index f2a35a5..cc28c50 100644
--- a/chromeos/audio/cras_audio_handler.h
+++ b/chromeos/audio/cras_audio_handler.h
@@ -99,6 +99,9 @@ class CHROMEOS_EXPORT CrasAudioHandler : public CrasAudioClient::Observer,
   // Returns true if the output volume is below the default mute volume level.
   virtual bool IsOutputVolumeBelowDefaultMuteLvel();
 
+  // Returns volume level in 0-100% range at which the volume should be muted.
+  virtual int GetOutputDefaultVolumeMuteThreshold();
+
   // Gets volume level in 0-100% range (0 being pure silence) for the current
   // active node.
   virtual int GetOutputVolumePercent();