A11y setting: mono audio UI

ash/system/tray_accessibility.cc

Index: ash/system/tray_accessibility.cc
diff --git a/ash/system/tray_accessibility.cc b/ash/system/tray_accessibility.cc
index 25a3de949aa4261eea3de8b591913e34f2d1db1d..30f16d3119feb6045fd361f06755cc1f214178e0 100644
--- a/ash/system/tray_accessibility.cc
+++ b/ash/system/tray_accessibility.cc
@@ -39,6 +39,7 @@ enum AccessibilityState {
   A11Y_AUTOCLICK = 1 << 4,
   A11Y_VIRTUAL_KEYBOARD = 1 << 5,
   A11Y_BRAILLE_DISPLAY_CONNECTED = 1 << 6,
+  A11Y_MONO_AUDIO = 1 << 7,
 };
 
 uint32_t GetAccessibilityState() {
@@ -59,6 +60,8 @@ uint32_t GetAccessibilityState() {
     state |= A11Y_VIRTUAL_KEYBOARD;
   if (delegate->IsBrailleDisplayConnected())
     state |= A11Y_BRAILLE_DISPLAY_CONNECTED;
+  if (delegate->IsMonoAudioEnabled())
+    state |= A11Y_MONO_AUDIO;
   return state;
 }
 
@@ -134,12 +137,14 @@ AccessibilityDetailedView::AccessibilityDetailedView(
         settings_view_(NULL),
         autoclick_view_(NULL),
         virtual_keyboard_view_(NULL),
+        mono_audio_view_(NULL),
         spoken_feedback_enabled_(false),
         high_contrast_enabled_(false),
         screen_magnifier_enabled_(false),
         large_cursor_enabled_(false),
         autoclick_enabled_(false),
         virtual_keyboard_enabled_(false),
+        mono_audio_enabled_(false),
         login_(login) {
 
   Reset();
@@ -288,6 +293,12 @@ void AccessibilityDetailedView::OnViewClicked(views::View* sender) {
             ash::UMA_STATUS_AREA_DISABLE_VIRTUAL_KEYBOARD :
             ash::UMA_STATUS_AREA_ENABLE_VIRTUAL_KEYBOARD);
     delegate->SetVirtualKeyboardEnabled(!delegate->IsVirtualKeyboardEnabled());
+  } else if (mono_audio_view_ && sender == mono_audio_view_) {
+    Shell::GetInstance()->metrics()->RecordUserMetricsAction(
+        delegate->IsMonoAudioEnabled() ?
+            ash::UMA_STATUS_AREA_DISABLE_MONO_AUDIO :
+            ash::UMA_STATUS_AREA_ENABLE_MONO_AUDIO);
+    delegate->SetMonoAudioEnabled(!delegate->IsMonoAudioEnabled());
   }
 }