Implement new slider control and disable the volume control when audio is muted.

ash/system/audio/tray_volume.cc

 // 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/audio/tray_volume.h"
 
 #include <cmath>
 
 #include "ash/shell.h"
 #include "ash/system/tray/system_tray_delegate.h"
@@ skipping 45 matching lines @@
   }
 
   virtual ~VolumeButton() {}
 
   void Update() {
     ash::SystemTrayDelegate* delegate =
         ash::Shell::GetInstance()->tray_delegate();
     float level = delegate->GetVolumeLevel();
     int image_index = delegate->IsAudioMuted() ?
         0 : (level == 1.0 ?
-             kVolumeLevels : std::ceil(level * (kVolumeLevels - 1)));
-
+             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::BS_NORMAL, &image_skia);
       image_index_ = image_index;
     }
     SchedulePaint();
   }
@@ skipping 25 matching lines @@
   void Update() {
     ash::SystemTrayDelegate* delegate =
         ash::Shell::GetInstance()->tray_delegate();
     UpdateButton(delegate->IsAudioMuted());
     SchedulePaint();
   }
 
   DISALLOW_COPY_AND_ASSIGN(MuteButton);
 };
 
+class VolumeSlider : public views::Slider {
+ public:
+  explicit VolumeSlider(views::SliderListener* listener)
+      : views::Slider(listener, views::Slider::HORIZONTAL) {
+    set_focus_border_color(kFocusBorderColor);
+    SetValue(ash::Shell::GetInstance()->tray_delegate()->GetVolumeLevel());
+    SetAccessibleName(
+            ui::ResourceBundle::GetSharedInstance().GetLocalizedString(
+                IDS_ASH_STATUS_TRAY_VOLUME));
+    Update();
+  }
+  virtual ~VolumeSlider() {}
+
+  void Update() {
+    UpdateState(!ash::Shell::GetInstance()->tray_delegate()->IsAudioMuted());
+  }
+
+  DISALLOW_COPY_AND_ASSIGN(VolumeSlider);
+};
+
 class VolumeView : public views::View,
                    public views::ButtonListener,
                    public views::SliderListener {
  public:
   VolumeView() {
     SetLayoutManager(new views::BoxLayout(views::BoxLayout::kHorizontal,
           kTrayPopupPaddingHorizontal, 0, kTrayPopupPaddingBetweenItems));
 
     icon_ = new VolumeButton(this);
     AddChildView(icon_);
 
     mute_ = new MuteButton(this);
     AddChildView(mute_);
 
-    ash::SystemTrayDelegate* delegate =
-        ash::Shell::GetInstance()->tray_delegate();
-    slider_ = new views::Slider(this, views::Slider::HORIZONTAL);
-    slider_->set_focus_border_color(kFocusBorderColor);
-    slider_->SetValue(
-        delegate->IsAudioMuted() ? 0.0 : delegate->GetVolumeLevel());
-    slider_->SetAccessibleName(
-        ui::ResourceBundle::GetSharedInstance().GetLocalizedString(
-            IDS_ASH_STATUS_TRAY_VOLUME));
+    slider_ = new VolumeSlider(this);
     AddChildView(slider_);
   }
 
   virtual ~VolumeView() {}
 
+  void Update() {
+    icon_->Update();
+    mute_->Update();
+    slider_->Update();
+  }
+
   void SetVolumeLevel(float percent) {
     // 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.
-    icon_->Update();
-    mute_->Update();
+    Update();
     slider_->set_enable_accessibility_events(true);
   }
 
  private:
   // Overridden from views::View.
   virtual void OnBoundsChanged(const gfx::Rect& old_bounds) OVERRIDE {
     int w = width() - slider_->x();
     slider_->SetSize(gfx::Size(w, slider_->height()));
   }
 
@@ skipping 14 matching lines @@
     if (reason == views::VALUE_CHANGED_BY_USER) {
       ash::SystemTrayDelegate* delegate =
           ash::Shell::GetInstance()->tray_delegate();
       delegate->SetVolumeLevel(value);
     }
     icon_->Update();
   }
 
   VolumeButton* icon_;
   MuteButton* mute_;
-  views::Slider* slider_;
+  VolumeSlider* slider_;
 
   DISALLOW_COPY_AND_ASSIGN(VolumeView);
 };
 
 }  // namespace tray
 
 TrayVolume::TrayVolume()
     : TrayImageItem(IDR_AURA_UBER_TRAY_VOLUME_MUTE),
       volume_view_(NULL),
       is_default_view_(false) {
 }
 
 TrayVolume::~TrayVolume() {
 }
 
 bool TrayVolume::GetInitialVisibility() {
   ash::SystemTrayDelegate* delegate =
       ash::Shell::GetInstance()->tray_delegate();
-  return delegate->GetVolumeLevel() == 0.0 || delegate->IsAudioMuted();
+  return delegate->IsAudioMuted();
 }
 
 views::View* TrayVolume::CreateDefaultView(user::LoginStatus status) {
   volume_view_ = new tray::VolumeView;
   is_default_view_ = true;
   return volume_view_;
 }
 
 views::View* TrayVolume::CreateDetailedView(user::LoginStatus status) {
   volume_view_ = new tray::VolumeView;
@@ skipping 18 matching lines @@
   if (volume_view_) {
     if (ash::Shell::GetInstance()->tray_delegate()->IsAudioMuted())
       percent = 0.0;
     volume_view_->SetVolumeLevel(percent);
     SetDetailedViewCloseDelay(kTrayPopupAutoCloseDelayInSeconds);
     return;
   }
   PopupDetailedView(kTrayPopupAutoCloseDelayInSeconds, false);
 }
 
+void TrayVolume::OnMuteToggled() {
+  if (tray_view())
+      tray_view()->SetVisible(GetInitialVisibility());
+
+  if (volume_view_)
+    volume_view_->Update();
+}
+
 }  // namespace internal
 }  // namespace ash