Make the mute button in the Ash system menu keyboard focusable

ash/common/system/audio/volume_view.cc

Index: ash/common/system/audio/volume_view.cc
diff --git a/ash/common/system/audio/volume_view.cc b/ash/common/system/audio/volume_view.cc
index 6435bac72442a11c2adea7f8446445d59eac75d7..53a0ce888a70996b348dbff895b272db1b0301cb 100644
--- a/ash/common/system/audio/volume_view.cc
+++ b/ash/common/system/audio/volume_view.cc
@@ -26,6 +26,7 @@
 #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;
@@ -54,9 +55,17 @@ class VolumeButton : public views::ToggleImageButton {
       : 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();
   }