Make the lifetime of wallpaper manager more clear.

chrome/browser/chromeos/login/users/wallpaper/wallpaper_manager.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 CHROME_BROWSER_CHROMEOS_LOGIN_USERS_WALLPAPER_WALLPAPER_MANAGER_H_
 #define CHROME_BROWSER_CHROMEOS_LOGIN_USERS_WALLPAPER_WALLPAPER_MANAGER_H_
 
 #include <deque>
 #include <string>
 #include <vector>
@@ skipping 19 matching lines @@
 #include "ui/gfx/image/image_skia.h"
 
 namespace chromeos {
 
 class WallpaperManager :
     public wallpaper::WallpaperManagerBase,
     public user_manager::UserManager::UserSessionStateObserver {
  public:
   class PendingWallpaper;
 
-  WallpaperManager();
   ~WallpaperManager() override;
 
   // Get pointer to singleton WallpaperManager instance, create it if necessary.
   static WallpaperManager* Get();
 
+  // Indicates imminent shutdown, allowing the WallpaperManager to remove any
+  // observers it has registered.
+  static void Shutdown();
+
   // Returns the appropriate wallpaper resolution for all root windows.
   WallpaperResolution GetAppropriateResolution() override;
 
-  // Indicates imminent shutdown, allowing the WallpaperManager to remove any
-  // observers it has registered.
-  void Shutdown() override;
-
   // Adds PowerManagerClient, TimeZoneSettings and CrosSettings observers.
   void AddObservers() override;
 
   // Loads wallpaper asynchronously if the current wallpaper is not the
   // wallpaper of logged in user.
   void EnsureLoggedInUserWallpaperLoaded() override;
 
   // Initializes wallpaper. If logged in, loads user's wallpaper. If not logged
   // in, uses a solid color wallpaper. If logged in as a stub user, uses an
   // empty wallpaper.
@@ skipping 57 matching lines @@
 
   // Overridden from user_manager::UserManager::UserSessionStateObserver:
   void UserChangedChildStatus(user_manager::User* user) override;
 
  private:
   friend class TestApi;
   friend class WallpaperManagerBrowserTest;
   friend class WallpaperManagerBrowserTestDefaultWallpaper;
   friend class WallpaperManagerPolicyTest;
 
+  WallpaperManager();
+
   // Returns modifiable PendingWallpaper.
   // Returns pending_inactive_ or creates new PendingWallpaper if necessary.
   PendingWallpaper* GetPendingWallpaper(const std::string& user_id,
                                         bool delayed);
 
   // This is called by PendingWallpaper when load is finished.
   void RemovePendingWallpaperFromList(PendingWallpaper* pending);
 
   // WallpaperManagerBase overrides:
   void ClearObsoleteWallpaperPrefs() override;
@@ skipping 53 matching lines @@
   typedef std::vector<scoped_refptr<PendingWallpaper> > PendingList;
   PendingList loading_;
 
   base::WeakPtrFactory<WallpaperManager> weak_factory_;
   DISALLOW_COPY_AND_ASSIGN(WallpaperManager);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_LOGIN_USERS_WALLPAPER_WALLPAPER_MANAGER_H_