Replace more ObserverList with base::ObserverList.

ui/snapshot/screenshot_grabber.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 UI_SNAPSHOT_SCREENSHOT_GRABBER_H_
 #define UI_SNAPSHOT_SCREENSHOT_GRABBER_H_
 
 #include "base/basictypes.h"
 #include "base/callback.h"
 #include "base/compiler_specific.h"
@@ skipping 72 matching lines @@
 
   // A weak pointer to the screenshot taker client.
   ScreenshotGrabberDelegate* client_;
 
   // The timestamp when the screenshot task was issued last time.
   base::TimeTicks last_screenshot_timestamp_;
 
   // Task runner for blocking tasks.
   scoped_refptr<base::TaskRunner> blocking_task_runner_;
 
-  ObserverList<ScreenshotGrabberObserver> observers_;
+  base::ObserverList<ScreenshotGrabberObserver> observers_;
   base::WeakPtrFactory<ScreenshotGrabber> factory_;
 
   DISALLOW_COPY_AND_ASSIGN(ScreenshotGrabber);
 };
 
 }  // namespace ui
 
 #endif  // UI_SNAPSHOT_SCREENSHOT_GRABBER_H_