chromeos: Rename ash::WmShelf to Shelf

ash/system/session/logout_button_tray.h

 // 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.
 
 #ifndef ASH_SYSTEM_SESSION_LOGOUT_BUTTON_TRAY_H_
 #define ASH_SYSTEM_SESSION_LOGOUT_BUTTON_TRAY_H_
 
 #include "ash/ash_export.h"
 #include "ash/system/session/logout_button_observer.h"
 #include "base/macros.h"
 #include "base/time/time.h"
 #include "ui/views/controls/button/button.h"
 #include "ui/views/view.h"
 
 namespace views {
 class MdTextButton;
 }
 
 namespace ash {
+class Shelf;
 class TrayContainer;
-class WmShelf;
 
 // Adds a logout button to the launcher's status area if enabled by the
 // kShowLogoutButtonInTray pref.
 class ASH_EXPORT LogoutButtonTray : public views::View,
                                     public LogoutButtonObserver,
                                     public views::ButtonListener {
  public:
-  explicit LogoutButtonTray(WmShelf* wm_shelf);
+  explicit LogoutButtonTray(Shelf* shelf);
   ~LogoutButtonTray() override;
 
   void UpdateAfterLoginStatusChange();
   void UpdateAfterShelfAlignmentChange();
 
   // views::View:
   void GetAccessibleNodeData(ui::AXNodeData* node_data) override;
 
   // LogoutButtonObserver:
   void OnShowLogoutButtonInTrayChanged(bool show) override;
   void OnLogoutDialogDurationChanged(base::TimeDelta duration) override;
 
   // views::ButtonListener:
   void ButtonPressed(views::Button* sender, const ui::Event& event) override;
 
  private:
   void UpdateVisibility();
   void UpdateButtonTextAndImage();
 
-  WmShelf* const wm_shelf_;
+  Shelf* const shelf_;
   TrayContainer* const container_;
   views::MdTextButton* const button_;
   bool show_logout_button_in_tray_;
   base::TimeDelta dialog_duration_;
 
   DISALLOW_COPY_AND_ASSIGN(LogoutButtonTray);
 };
 
 }  // namespace ash
 
 #endif  // ASH_SYSTEM_SESSION_LOGOUT_BUTTON_TRAY_H_