A11y setting: mono audio UI

ash/shell.cc

Index: ash/shell.cc
diff --git a/ash/shell.cc b/ash/shell.cc
index b4972ec0a3a2024221a3e77d605e06c855dc8caa..2b0b559d14af867f91c2c0a111cb7935a0998124 100644
--- a/ash/shell.cc
+++ b/ash/shell.cc
@@ -140,6 +140,7 @@
 #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"
@@ -817,6 +818,10 @@ Shell::~Shell() {
   touch_transformer_controller_.reset();
 #endif  // defined(OS_CHROMEOS)
 
+#if defined(OS_CHROMEOS)
+  audio_a11y_controller_.reset();
+#endif  // defined(OS_CHROMEOS)
+
   // This also deletes all RootWindows. Note that we invoke Shutdown() on
   // WindowTreeHostManager before resetting |window_tree_host_manager_|, since
   // destruction
@@ -1093,6 +1098,10 @@ 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