components: Cleanup class/struct fwd declarations

components/history/core/browser/history_database.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_HISTORY_DATABASE_H_
 #define COMPONENTS_HISTORY_CORE_BROWSER_HISTORY_DATABASE_H_
 
 #include <stddef.h>
 
 #include "base/compiler_specific.h"
@@ skipping 11 matching lines @@
 
 #if defined(OS_ANDROID)
 #include "components/history/core/browser/android/android_cache_database.h"
 #include "components/history/core/browser/android/android_urls_database.h"
 #endif
 
 namespace base {
 class FilePath;
 }
 
-class HistoryQuickProviderTest;
 class InMemoryURLIndexTest;
 
 namespace history {
 
 // Encapsulates the SQL connection for the history database. This class holds
 // the database connection and has methods the history system (including full
 // text search) uses for writing and retrieving information.
 //
 // We try to keep most logic out of the history database; this should be seen
 // as the storage interface. Logic for manipulating this storage layer should
@@ skipping 152 matching lines @@
   sql::MetaTable meta_table_;
 
   base::Time cached_early_expiration_threshold_;
 
   DISALLOW_COPY_AND_ASSIGN(HistoryDatabase);
 };
 
 }  // namespace history
 
 #endif  // COMPONENTS_HISTORY_CORE_BROWSER_HISTORY_DATABASE_H_