Delay wallpaper load by 2 * average wallpaper load time.

chrome/browser/chromeos/login/wallpaper_manager.h

Index: chrome/browser/chromeos/login/wallpaper_manager.h
diff --git a/chrome/browser/chromeos/login/wallpaper_manager.h b/chrome/browser/chromeos/login/wallpaper_manager.h
index cbf7af5add84640df06e6fce247545246c42ce98..8560d274b9dab0e690f9705e82f8c6302f79e712 100644
--- a/chrome/browser/chromeos/login/wallpaper_manager.h
+++ b/chrome/browser/chromeos/login/wallpaper_manager.h
@@ -64,7 +64,7 @@ extern const char kThumbnailWallpaperSubDir[];
 
 // This class maintains wallpapers for users who have logged into this Chrome
 // OS device.
-class WallpaperManager: public content::NotificationObserver {
+class WallpaperManager : public content::NotificationObserver {
  public:
   // For testing.
   class TestApi {
@@ -80,6 +80,14 @@ class WallpaperManager: public content::NotificationObserver {
     DISALLOW_COPY_AND_ASSIGN(TestApi);
   };
 
+  class Observer : public base::RefCounted<Observer> {
+   public:
+    virtual ~Observer() {};
+    virtual void OnWallpaperAnimationFinished(const std::string& email) = 0;
+  };
+
+  typedef std::list<base::WeakPtr<Observer> > ObserverList;

[dzhioev (left Google), 2013/10/17 12:47:49]

Use ObserverList from base/observer_list.h

+
   static WallpaperManager* Get();
 
   WallpaperManager();
@@ -187,6 +195,9 @@ class WallpaperManager: public content::NotificationObserver {
   // current display's resolution.
   void UpdateWallpaper();
 
+  // Adds given observer to the list.
+  void AddObserver(base::WeakPtr<Observer> observer);
+
  private:
   friend class TestApi;
   friend class WallpaperManagerBrowserTest;
@@ -287,6 +298,9 @@ class WallpaperManager: public content::NotificationObserver {
                  bool update_wallpaper,
                  const base::FilePath& wallpaper_path);
 
+  // Notify all registed observers.
+  void NotifyAnimationFinished();
+
   // The number of loaded wallpapers.
   int loaded_wallpapers_;
 
@@ -323,6 +337,8 @@ class WallpaperManager: public content::NotificationObserver {
 
   content::NotificationRegistrar registrar_;
 
+  ObserverList observers_;
+
   DISALLOW_COPY_AND_ASSIGN(WallpaperManager);
 };