chromeos: Move SystemTrayDelegate::RequestShutdown to WmShell

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 7da0202ebb186ee19d1a2005cfe683440a0ffb99..2d59990720296339935609efaafa94c635b8b13c 100644
--- a/ash/aura/wm_shell_aura.cc
+++ b/ash/aura/wm_shell_aura.cc
@@ -24,6 +24,7 @@
 #include "ash/shell.h"
 #include "ash/touch/touch_uma.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"
@@ -282,6 +283,10 @@ 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();
 }