chrome: Cleanup class/struct forward declarations

chrome/browser/chromeos/extensions/file_system_provider/provider_function.h

 // Copyright 2014 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_CHROMEOS_EXTENSIONS_FILE_SYSTEM_PROVIDER_PROVIDER_FUNCTION_H_
 #define CHROME_BROWSER_CHROMEOS_EXTENSIONS_FILE_SYSTEM_PROVIDER_PROVIDER_FUNCTION_H_
 
 #include <memory>
 #include <string>
 
 #include "base/files/file.h"
 #include "chrome/browser/extensions/chrome_extension_function.h"
 #include "chrome/common/extensions/api/file_system_provider.h"
 
-namespace base {
-class DictionaryValue;
-}  // namespace base
-
 namespace chromeos {
 namespace file_system_provider {
 
 class RequestManager;
 class RequestValue;
 
 }  // namespace file_system_provider
 }  // namespace chromeos
 
 namespace extensions {
@@ skipping 45 matching lines @@
   // Guarantees |request_id_| and |request_manager_| are valid.
   bool PreRunValidation(std::string* error) override;
 
   int request_id_;
   chromeos::file_system_provider::RequestManager* request_manager_;
 };
 
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_CHROMEOS_EXTENSIONS_FILE_SYSTEM_PROVIDER_PROVIDER_FUNCTION_H_