components: Cleanup class/struct fwd declarations

components/data_reduction_proxy/core/browser/db_data_owner.h

 // Copyright 2015 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_DATA_REDUCTION_PROXY_CORE_BROWSER_DB_SERVICE_H_
 #define COMPONENTS_DATA_REDUCTION_PROXY_CORE_BROWSER_DB_SERVICE_H_
 
 #include <memory>
 #include <vector>
 
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "base/sequence_checker.h"
 
-namespace base {
-class FilePath;
-}  // namespace base
-
 namespace data_reduction_proxy {
 class DataStore;
 class DataUsageBucket;
 class DataUsageStore;
 
 // Callback for loading the historical data usage.
 typedef base::Callback<void(std::unique_ptr<std::vector<DataUsageBucket>>)>
     HistoricalDataUsageCallback;
 
 // Callback for loading data usage for the current bucket.
@@ skipping 32 matching lines @@
   std::unique_ptr<DataStore> store_;
   std::unique_ptr<DataUsageStore> data_usage_;
   base::SequenceChecker sequence_checker_;
   base::WeakPtrFactory<DBDataOwner> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(DBDataOwner);
 };
 
 }  // namespace data_reduction_proxy
 #endif  // COMPONENTS_DATA_REDUCTION_PROXY_CORE_BROWSER_DB_SERVICE_H_