mash: Make the power button shut the system down.

ash/aura/wm_shell_aura.cc

Index: ash/aura/wm_shell_aura.cc
diff --git a/ash/aura/wm_shell_aura.cc b/ash/aura/wm_shell_aura.cc
index 01127cf3893d76cb86a69fea8e2b2867cb403b8b..2643fa3039a71d666556cc78d355d32094d34492 100644
--- a/ash/aura/wm_shell_aura.cc
+++ b/ash/aura/wm_shell_aura.cc
@@ -26,7 +26,6 @@
 #include "ash/touch/touch_uma.h"
 #include "ash/virtual_keyboard_controller.h"
 #include "ash/wm/drag_window_resizer.h"
-#include "ash/wm/lock_state_controller.h"
 #include "ash/wm/maximize_mode/maximize_mode_event_handler_aura.h"
 #include "ash/wm/screen_pinning_controller.h"
 #include "ash/wm/window_cycle_event_filter_aura.h"
@@ -263,10 +262,6 @@ void WmShellAura::RemovePointerWatcher(views::PointerWatcher* watcher) {
   pointer_watcher_adapter_->RemovePointerWatcher(watcher);
 }
 
-void WmShellAura::RequestShutdown() {
-  Shell::GetInstance()->lock_state_controller()->RequestShutdown();
-}
-
 bool WmShellAura::IsTouchDown() {
   return aura::Env::GetInstance()->is_touch_down();
 }