ash: Constantify user methods of SystemTrayDelegate.

ash/system/tray/system_tray_delegate.h

 // 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.
 
 #ifndef ASH_SYSTEM_TRAY_SYSTEM_TRAY_DELEGATE_H_
 #define ASH_SYSTEM_TRAY_SYSTEM_TRAY_DELEGATE_H_
 #pragma once
 
 #include "ash/system/user/login_status.h"
 
 class SkBitmap;
 
 namespace ash {
 
 class SystemTrayDelegate {
  public:
   virtual ~SystemTrayDelegate() {}
 
   // Gets information about the logged in user.
-  virtual const std::string GetUserDisplayName() = 0;
-  virtual const std::string GetUserEmail() = 0;
-  virtual const SkBitmap& GetUserImage() = 0;
-  virtual user::LoginStatus GetUserLoginStatus() = 0;
+  virtual const std::string GetUserDisplayName() const = 0;
+  virtual const std::string GetUserEmail() const = 0;
+  virtual const SkBitmap& GetUserImage() const = 0;
+  virtual user::LoginStatus GetUserLoginStatus() const = 0;
 
   // Shows settings.
   virtual void ShowSettings() = 0;
 
   // Shows help.
   virtual void ShowHelp() = 0;
 
   // Is the system audio muted?
   virtual bool IsAudioMuted() const = 0;
 
@@ skipping 12 matching lines @@
   // Attempts to sign out the user.
   virtual void SignOut() = 0;
 
   // Attempts to lock the screen.
   virtual void LockScreen() = 0;
 };
 
 }  // namespace ash
 
 #endif  // ASH_SYSTEM_TRAY_SYSTEM_TRAY_DELEGATE_H_