Move even more from WmShell to Shell

ash/wm/power_button_controller.cc

 // Copyright (c) 2012 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/wm/power_button_controller.h"
 
 #include "ash/common/accelerators/accelerator_controller.h"
 #include "ash/common/ash_switches.h"
 #include "ash/common/session/session_controller.h"
 #include "ash/common/system/chromeos/audio/tray_audio.h"
@@ skipping 50 matching lines @@
 
 void PowerButtonController::OnPowerButtonEvent(
     bool down,
     const base::TimeTicks& timestamp) {
   power_button_down_ = down;
 
   if (lock_state_controller_->ShutdownRequested())
     return;
 
   bool should_take_screenshot = down && volume_down_pressed_ &&
-                                WmShell::Get()
+                                Shell::Get()
                                     ->maximize_mode_controller()
                                     ->IsMaximizeModeWindowManagerEnabled();
 
   if (!has_legacy_power_button_ && !should_take_screenshot &&
       tablet_controller_ &&
       tablet_controller_->ShouldHandlePowerButtonEvents()) {
     tablet_controller_->OnPowerButtonEvent(down, timestamp);
     return;
   }
 
@@ skipping 109 matching lines @@
       internal_display_off && external_display_on;
 }
 
 void PowerButtonController::PowerButtonEventReceived(
     bool down,
     const base::TimeTicks& timestamp) {
   OnPowerButtonEvent(down, timestamp);
 }
 
 }  // namespace ash