Reduce the amount of included header files. Vast change like in "Oh God! This...

chrome/common/pref_service.h

 // Copyright (c) 2006-2008 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.
 
 // This provides a way to access the application's current preferences.
 // This service has two preference stores, one for "persistent" preferences,
 // which get serialized for use in the next session, and one for "transient"
 // preferences, which are in effect for only the current session
 // (this usually encodes things like command-line switches).
 //
 // Calling the getter functions in this class basically looks at both the
 // persistent and transient stores, where any corresponding value in the
 // transient store overrides the one in the persistent store.
 
 #ifndef CHROME_COMMON_PREF_SERVICE_H_
 #define CHROME_COMMON_PREF_SERVICE_H_
 
-#include <string>
+#include <set>
 
-#include "base/basictypes.h"
 #include "base/hash_tables.h"
 #include "base/non_thread_safe.h"
 #include "base/observer_list.h"
 #include "base/scoped_ptr.h"
 #include "base/task.h"
 #include "base/values.h"
 #include "testing/gtest/include/gtest/gtest_prod.h"
 
 class NotificationObserver;
 class Preference;
@@ skipping 200 matching lines @@
   // order they are added.
   typedef ObserverList<NotificationObserver> NotificationObserverList;
   typedef base::hash_map<std::wstring, NotificationObserverList*>
       PrefObserverMap;
   PrefObserverMap pref_observers_;
 
   DISALLOW_COPY_AND_ASSIGN(PrefService);
 };
 
 #endif  // CHROME_COMMON_PREF_SERVICE_H_