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

ash/system/audio/volume_view.cc

Index: ash/system/audio/volume_view.cc
diff --git a/ash/system/audio/volume_view.cc b/ash/system/audio/volume_view.cc
new file mode 100644
index 0000000000000000000000000000000000000000..bce083a43b6a0e890922c49731740110036b630b
--- /dev/null
+++ b/ash/system/audio/volume_view.cc
@@ -0,0 +1,329 @@
+// 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/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:
+  explicit VolumeButton(views::ButtonListener* listener,
+                        system::TrayAudioDelegate& audio_delegate)

[jennyz, 2014/02/14 21:36:43]

Remove explicit, no need if there are more than one arguments for constructor.

[zturner, 2014/02/15 00:57:45]

Done.

+      : 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:
+  explicit VolumeSlider(views::SliderListener* listener,
+                        system::TrayAudioDelegate& audio_delegate)

[jennyz, 2014/02/14 21:36:43]

Remove explicit. Why not just pass system::TrayAudioDelegate*?

[zturner, 2014/02/15 00:57:45]

Done.

+      : 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_.GetDeviceIconId();
+  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);
+  }

[jennyz, 2014/02/14 21:36:43]

You removed the else if case in original HandleVolumeDown, please make sure the
volume control behaves correctly in that case.
else if (!audio_handler->IsOutputVolumeBelowDefaultMuteLvel() &&
               audio_handler->IsOutputMuted()) {
      audio_handler->SetOutputMute(false);
    }

It has been a long time, I don't remember exactly which case this handles,
please make sure the volumecontrol browser tests all passed. I think the most
edge cases are covered there.

[zturner, 2014/02/15 00:57:45]

I added this back.  I think I removed it because the condition didn't make sense
to me and it looked like a bug, but on second thought since this is supposed to
be a pure refactor with no functional change, it doesn't make sense for me to
remove it.

+}
+
+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