A11y setting: mono audio UI

ash/shell.cc

Index: ash/shell.cc
diff --git a/ash/shell.cc b/ash/shell.cc
index 2e100f0b942c8c5f1756d08d3f1e05455580f90d..dc9336d25e635a65fc5d02c6f6cc6b9c630852e8 100644
--- a/ash/shell.cc
+++ b/ash/shell.cc
@@ -139,6 +139,7 @@
 #include "ash/virtual_keyboard_controller.h"
 #include "base/bind_helpers.h"
 #include "base/sys_info.h"
+#include "chromeos/audio/audio_a11y_controller.h"
 #include "chromeos/dbus/dbus_thread_manager.h"
 #include "ui/chromeos/user_activity_power_manager_notifier.h"
 #include "ui/display/chromeos/display_configurator.h"
@@ -761,6 +762,10 @@ Shell::~Shell() {
   video_detector_.reset();
   high_contrast_controller_.reset();
 
+#if defined(OS_CHROMEOS)
+  audio_a11y_controller_.reset();
+#endif  // defined(OS_CHROMEOS)
+
   shadow_controller_.reset();
   resize_shadow_controller_.reset();
 
@@ -1091,6 +1096,10 @@ void Shell::Init(const ShellInitParams& init_params) {
   virtual_keyboard_controller_.reset(new VirtualKeyboardController);
 #endif  // defined(OS_CHROMEOS)
 
+#if defined(OS_CHROMEOS)
+  audio_a11y_controller_.reset(new chromeos::AudioA11yController);
+#endif  // defined(OS_CHROMEOS)
+
   // It needs to be created after RootWindowController has been created
   // (which calls OnWindowResized has been called, otherwise the
   // widget will not paint when restoring after a browser crash.  Also it needs