Replace more ObserverList with base::ObserverList.

extensions/browser/extension_icon_image.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 EXTENSIONS_BROWSER_EXTENSION_ICON_IMAGE_H_
 #define EXTENSIONS_BROWSER_EXTENSION_ICON_IMAGE_H_
 
 #include <map>
 #include <string>
 
@@ skipping 87 matching lines @@
   // content::NotificationObserver overrides:
   void Observe(int type,
                const content::NotificationSource& source,
                const content::NotificationDetails& details) override;
 
   content::BrowserContext* browser_context_;
   const Extension* extension_;
   const ExtensionIconSet& icon_set_;
   const int resource_size_in_dip_;
 
-  ObserverList<Observer> observers_;
+  base::ObserverList<Observer> observers_;
 
   Source* source_;  // Owned by ImageSkia storage.
   gfx::ImageSkia image_skia_;
   // The icon with whose representation |image_skia_| should be updated if
   // its own representation load fails.
   gfx::ImageSkia default_icon_;
 
   // The image wrapper around |image_skia_|.
   // Note: this is reset each time a new representation is loaded.
   gfx::Image image_;
 
   content::NotificationRegistrar registrar_;
 
   base::WeakPtrFactory<IconImage> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(IconImage);
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_BROWSER_EXTENSION_ICON_IMAGE_H_