Make the mute button in the Ash system menu keyboard focusable

ash/common/system/audio/volume_view.cc

 // 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/common/system/audio/volume_view.h"
 
 #include "ash/common/ash_constants.h"
 #include "ash/common/material_design/material_design_controller.h"
 #include "ash/common/metrics/user_metrics_action.h"
 #include "ash/common/system/audio/tray_audio.h"
 #include "ash/common/system/audio/tray_audio_delegate.h"
 #include "ash/common/system/tray/system_tray_item.h"
 #include "ash/common/system/tray/tray_constants.h"
 #include "ash/common/system/tray/tray_popup_item_container.h"
 #include "ash/common/wm_shell.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/gfx/paint_vector_icon.h"
 #include "ui/gfx/vector_icons_public.h"
 #include "ui/views/background.h"
 #include "ui/views/border.h"
 #include "ui/views/controls/button/image_button.h"
 #include "ui/views/controls/image_view.h"
 #include "ui/views/controls/separator.h"
 #include "ui/views/layout/box_layout.h"
+#include "ui/views/painter.h"
 
 namespace {
 const int kVolumeImageWidth = 25;
 const int kVolumeImageHeight = 25;
 const int kSeparatorSize = 3;
 const int kSeparatorVerticalInset = 8;
 const int kSliderRightPaddingToVolumeViewEdge = 17;
 const int kExtraPaddingBetweenBarAndMore = 10;
 const int kExtraPaddingBetweenIconAndSlider = 8;
 const int kBoxLayoutPadding = 2;
 
 // 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 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) {
+    ui::ResourceBundle& bundle = ui::ResourceBundle::GetSharedInstance();
+
+    SetFocusBehavior(FocusBehavior::ALWAYS);
+    SetFocusPainter(views::Painter::CreateSolidFocusPainter(
+        kFocusBorderColor, gfx::Insets(1, 1, 1, 1)));
+    SetAccessibleName(

[David Tseng, 2016/08/10 15:41:02]

Could you override View::GetAccessibleState(AXViewState* state) and set the
following:
state->role = ui::AX_ROLE_TOGGLE_BUTTON;
and
state->AddStateFlag(ui::AX_STATE_PRESSED);
if audio is muted
in addition to
state->name

[tdanderson, 2016/08/10 20:24:33]

If I'm understanding the code correctly, it looks like all of that is handled by
views::ToggleImageButton::GetAccessibleState(), so I don't think that
VolumeButton needs to override GetAccessibleState() too. Can you please clarify?

+        bundle.GetLocalizedString(IDS_ASH_STATUS_TRAY_VOLUME_MUTE));
+
     SetImageAlignment(ALIGN_CENTER, ALIGN_MIDDLE);
-    image_ = ui::ResourceBundle::GetSharedInstance().GetImageNamed(
-        IDR_AURA_UBER_TRAY_VOLUME_LEVELS);
+    image_ = bundle.GetImageNamed(IDR_AURA_UBER_TRAY_VOLUME_LEVELS);
+
     Update();
   }
 
   ~VolumeButton() override {}
 
   void Update() {
     float level =
         static_cast<float>(audio_delegate_->GetOutputVolumeLevel()) / 100.0f;
     int image_index =
         audio_delegate_->IsOutputAudioMuted()
@@ skipping 220 matching lines @@
   separator_->SetSize(gfx::Size(kSeparatorSize, bounds().height()));
 }
 
 void VolumeView::GetAccessibleState(ui::AXViewState* state) {
   // Intentionally overrides ActionableView, leaving |state| unset. A slider
   // childview exposes accessibility data.
 }
 
 }  // namespace tray
 }  // namespace ash