components: Cleanup class/struct fwd declarations

components/history/core/browser/top_sites.h

 // Copyright (c) 2012 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 COMPONENTS_HISTORY_CORE_BROWSER_TOP_SITES_H_
 #define COMPONENTS_HISTORY_CORE_BROWSER_TOP_SITES_H_
 
 #include <vector>
 
 #include "base/callback.h"
 #include "base/macros.h"
 #include "base/observer_list.h"
 #include "base/task/cancelable_task_tracker.h"
 #include "components/history/core/browser/history_types.h"
 #include "components/history/core/browser/top_sites_observer.h"
 #include "components/history/core/common/thumbnail_score.h"
 #include "components/keyed_service/core/refcounted_keyed_service.h"
 #include "third_party/skia/include/core/SkColor.h"
 #include "ui/gfx/image/image.h"
 
 class GURL;
 
 namespace base {
-class FilePath;
-class RefCountedBytes;
 class RefCountedMemory;
 }
 
 namespace history {
 
-class TopSitesCache;
 class TopSitesObserver;
 
 // PrepopulatedPage stores information for prepopulated page for the
 // initial run.
 struct PrepopulatedPage {
   PrepopulatedPage();
   PrepopulatedPage(const GURL& url,
                    const base::string16& title,
                    int favicon_id,
                    int thumbnail_id,
@@ skipping 143 matching lines @@
   friend class base::RefCountedThreadSafe<TopSites>;
 
   base::ObserverList<TopSitesObserver, true> observer_list_;
 
   DISALLOW_COPY_AND_ASSIGN(TopSites);
 };
 
 }  // namespace history
 
 #endif  // COMPONENTS_HISTORY_CORE_BROWSER_TOP_SITES_H_