Promotes more accessors from WmShell to Shell

ash/system/chromeos/power/power_event_observer.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ash/system/chromeos/power/power_event_observer.h"
 
 #include "ash/common/session/session_controller.h"
 #include "ash/common/system/tray/system_tray_notifier.h"
 #include "ash/common/wm_shell.h"
 #include "ash/shell.h"
@@ skipping 116 matching lines @@
                                          ->GetPowerManagerClient()
                                          ->GetSuspendReadinessCallback()));
   }
 }
 
 void PowerEventObserver::SuspendDone(const base::TimeDelta& sleep_duration) {
   // TODO(derat): After mus exposes a method for resuming displays, call it
   // here: http://crbug.com/692193
   if (!WmShell::Get()->IsRunningInMash())
     Shell::GetInstance()->display_configurator()->ResumeDisplays();
-  WmShell::Get()->system_tray_notifier()->NotifyRefreshClock();
+  Shell::Get()->system_tray_notifier()->NotifyRefreshClock();
 
   // If the suspend request was being blocked while waiting for the lock
   // animation to complete, clear the blocker since the suspend has already
   // completed.  This prevents rendering requests from being blocked after a
   // resume if the lock screen took too long to show.
   screen_lock_callback_.Reset();
 
   ResumeRenderingRequests();
 }
 
 void PowerEventObserver::ScreenIsLocked() {
   screen_locked_ = true;
   waiting_for_lock_screen_animations_ = true;
 
   // The screen is now locked but the pending suspend, if any, will be blocked
   // until all the animations have completed.
   if (!screen_lock_callback_.is_null()) {
     VLOG(1) << "Screen locked due to suspend";
   } else {
     VLOG(1) << "Screen locked without suspend";
   }
 }
 
 void PowerEventObserver::ScreenIsUnlocked() {
   screen_locked_ = false;
 }
 
 }  // namespace ash