Cleanup: Remove forward declarations in various chrome/browser directories.

chrome/browser/history/history.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_HISTORY_HISTORY_H_
 #define CHROME_BROWSER_HISTORY_HISTORY_H_
 #pragma once
 
 #include <set>
 #include <vector>
@@ skipping 14 matching lines @@
 #include "content/public/browser/notification_registrar.h"
 #include "content/public/common/page_transition_types.h"
 #include "sql/init_status.h"
 
 class BookmarkService;
 struct DownloadPersistentStoreInfo;
 class FilePath;
 class GURL;
 class HistoryURLProvider;
 struct HistoryURLProviderParams;
-class InMemoryURLDatabase;
-class MainPagesRequest;
 class PageUsageData;
 class PageUsageRequest;
 class Profile;
-class SkBitmap;
-struct ThumbnailScore;
 
 namespace base {
 class Thread;
 class Time;
 }
 
-namespace browser_sync {
-class HistoryModelWorker;
-class TypedUrlDataTypeController;
-}
-
-namespace gfx {
-class Image;
-}
-
 namespace history {
 class InMemoryHistoryBackend;
 class InMemoryURLIndex;
 class HistoryAddPageArgs;
 class HistoryBackend;
 class HistoryDatabase;
 struct HistoryDetails;
 class HistoryQueryTest;
 class URLDatabase;
 }  // namespace history
@@ skipping 803 matching lines @@
   BookmarkService* bookmark_service_;
   bool no_db_;
 
   // True if needs top site migration.
   bool needs_top_sites_migration_;
 
   DISALLOW_COPY_AND_ASSIGN(HistoryService);
 };
 
 #endif  // CHROME_BROWSER_HISTORY_HISTORY_H_