Moves maintaining ShellObservers back to Shell

ash/display/screen_orientation_controller_chromeos.cc

 // Copyright 2014 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/display/screen_orientation_controller_chromeos.h"
 
 #include "ash/common/ash_switches.h"
 #include "ash/common/wm/maximize_mode/maximize_mode_controller.h"
 #include "ash/common/wm_shell.h"
 #include "ash/common/wm_window.h"
@@ skipping 50 matching lines @@
 
 }  // namespace
 
 ScreenOrientationController::ScreenOrientationController()
     : natural_orientation_(GetDisplayNaturalOrientation()),
       ignore_display_configuration_updates_(false),
       rotation_locked_(false),
       rotation_locked_orientation_(blink::WebScreenOrientationLockAny),
       user_rotation_(display::Display::ROTATE_0),
       current_rotation_(display::Display::ROTATE_0) {
-  WmShell::Get()->AddShellObserver(this);
+  Shell::GetInstance()->AddShellObserver(this);
 }
 
 ScreenOrientationController::~ScreenOrientationController() {
-  WmShell::Get()->RemoveShellObserver(this);
+  Shell::GetInstance()->RemoveShellObserver(this);
   chromeos::AccelerometerReader::GetInstance()->RemoveObserver(this);
   WmShell::Get()->RemoveDisplayObserver(this);
   Shell::GetInstance()->activation_client()->RemoveObserver(this);
   for (auto& windows : locking_windows_)
     windows.first->aura_window()->RemoveObserver(this);
 }
 
 void ScreenOrientationController::AddObserver(Observer* observer) {
   observers_.AddObserver(observer);
 }
@@ skipping 335 matching lines @@
 }
 
 bool ScreenOrientationController::CanRotateInLockedState() {
   return rotation_locked_orientation_ ==
              blink::WebScreenOrientationLockLandscape ||
          rotation_locked_orientation_ ==
              blink::WebScreenOrientationLockPortrait;
 }
 
 }  // namespace ash