iwyu: Use callback_old.h where appropriate, part 2.

chrome/browser/extensions/extension_accessibility_api.h

 // Copyright (c) 2011 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_EXTENSIONS_EXTENSION_ACCESSIBILITY_API_H_
 #define CHROME_BROWSER_EXTENSIONS_EXTENSION_ACCESSIBILITY_API_H_
 #pragma once
 
 #include <string>
 #include <vector>
 
-#include "base/callback.h"
+#include "base/callback_old.h"
 #include "base/memory/singleton.h"
 #include "base/values.h"
 #include "chrome/browser/accessibility_events.h"
 #include "chrome/browser/extensions/extension_function.h"
 #include "content/common/notification_observer.h"
 #include "content/common/notification_registrar.h"
 
 // Observes the profile and routes accessibility notifications as events
 // to the extension system.
 class ExtensionAccessibilityEventRouter : public NotificationObserver {
@@ skipping 68 matching lines @@
 
 // API function that returns the most recent focused control.
 class GetFocusedControlFunction : public SyncExtensionFunction {
   virtual ~GetFocusedControlFunction() {}
   virtual bool RunImpl();
   DECLARE_EXTENSION_FUNCTION_NAME(
       "experimental.accessibility.getFocusedControl")
 };
 
 #endif  // CHROME_BROWSER_EXTENSIONS_EXTENSION_ACCESSIBILITY_API_H_