Delete obviously unneeded forward declarations in chrome/browser/*.h.

chrome/browser/visitedlink_master.h

 // Copyright (c) 2010 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_VISITEDLINK_MASTER_H__
 #define CHROME_BROWSER_VISITEDLINK_MASTER_H__
 #pragma once
 
 #if defined(OS_WIN)
 #include <windows.h>
 #endif
 #include <set>
 #include <string>
 #include <vector>
 
 #include "base/file_path.h"
 #include "base/gtest_prod_util.h"
 #include "base/ref_counted.h"
 #include "base/shared_memory.h"
 #include "chrome/browser/history/history.h"
 #include "chrome/common/visitedlink_common.h"
 
 class GURL;
-class MessageLoop;
 class Profile;
 
 // Controls the link coloring database. The master controls all writing to the
 // database as well as disk I/O. There should be only one master.
 //
 // This class will defer writing operations to the file thread. This means that
 // class destruction, the file may still be open since operations are pending on
 // another thread.
 class VisitedLinkMaster : public VisitedLinkCommon {
  public:
@@ skipping 346 matching lines @@
   int32 used_count = 0;
   for (int32 i = 0; i < table_length_; i++) {
     if (hash_table_[i])
       used_count++;
   }
   DCHECK_EQ(used_count, used_items_);
 }
 #endif
 
 #endif  // CHROME_BROWSER_VISITEDLINK_MASTER_H__