chromeos: Move device shutdown handling out of chrome into ash

ash/common/wm_shell.h

Index: ash/common/wm_shell.h
diff --git a/ash/common/wm_shell.h b/ash/common/wm_shell.h
index da548cf30f7e2251a1f53703d71670a1f14ea479..2c7a1548972c36a3c193ec513650f6f6a71cd521 100644
--- a/ash/common/wm_shell.h
+++ b/ash/common/wm_shell.h
@@ -62,6 +62,7 @@ class ShelfModel;
 class ShelfWindowWatcher;
 class ShellDelegate;
 class ShellObserver;
+class ShutdownController;
 class SystemTrayDelegate;
 class SystemTrayController;
 class SystemTrayNotifier;
@@ -157,6 +158,10 @@ class ASH_EXPORT WmShell {
 
   ShelfModel* shelf_model();
 
+  ShutdownController* shutdown_controller() {
+    return shutdown_controller_.get();
+  }
+
   SystemTrayController* system_tray_controller() {
     return system_tray_controller_.get();
   }
@@ -485,6 +490,7 @@ class ASH_EXPORT WmShell {
   std::unique_ptr<ShelfController> shelf_controller_;
   std::unique_ptr<ShelfDelegate> shelf_delegate_;
   std::unique_ptr<ShelfWindowWatcher> shelf_window_watcher_;
+  std::unique_ptr<ShutdownController> shutdown_controller_;
   std::unique_ptr<SystemTrayController> system_tray_controller_;
   std::unique_ptr<SystemTrayNotifier> system_tray_notifier_;
   std::unique_ptr<SystemTrayDelegate> system_tray_delegate_;