components: Cleanup class/struct fwd declarations

components/webdata/common/web_data_service_base.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_WEBDATA_COMMON_WEB_DATA_SERVICE_BASE_H_
 #define COMPONENTS_WEBDATA_COMMON_WEB_DATA_SERVICE_BASE_H_
 
 #include "base/callback.h"
 #include "base/files/file_path.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/ref_counted_delete_on_message_loop.h"
 #include "components/webdata/common/webdata_export.h"
 #include "sql/init_status.h"
 
 class WebDatabase;
 class WebDatabaseService;
-class WebDatabaseTable;
 
 namespace base {
 // TODO(skyostil): Migrate to SingleThreadTaskRunner (crbug.com/465354).
 class SingleThreadTaskRunner;
-class Thread;
 }
 
 // Base for WebDataService class hierarchy.
 // WebDataServiceBase is destroyed on the UI thread.
 class WEBDATA_EXPORT WebDataServiceBase
     : public base::RefCountedDeleteOnMessageLoop<WebDataServiceBase> {
  public:
   // All requests return an opaque handle of the following type.
   typedef int Handle;
 
@@ skipping 60 matching lines @@
   // Our database service.
   scoped_refptr<WebDatabaseService> wdbs_;
 
  private:
   ProfileErrorCallback profile_error_callback_;
 
   DISALLOW_COPY_AND_ASSIGN(WebDataServiceBase);
 };
 
 #endif  // COMPONENTS_WEBDATA_COMMON_WEB_DATA_SERVICE_BASE_H_