Cleanup: Remove unneeded forward declarations in ppapi.

ppapi/shared_impl/url_request_info_impl.h

 // Copyright (c) 2011 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 PPAPI_SHARED_IMPL_URL_REQUEST_INFO_IMPL_H_
 #define PPAPI_SHARED_IMPL_URL_REQUEST_INFO_IMPL_H_
 
 #include <string>
 #include <vector>
 
 #include "base/compiler_specific.h"
 #include "ppapi/shared_impl/resource.h"
 #include "ppapi/thunk/ppb_url_request_info_api.h"
 
 namespace ppapi {
 
-namespace thunk {
-class PPB_FileRef_API;
-}
-
 struct PPAPI_SHARED_EXPORT PPB_URLRequestInfo_Data {
   struct PPAPI_SHARED_EXPORT BodyItem {
     BodyItem();
     explicit BodyItem(const std::string& data);
     BodyItem(Resource* file_ref,
              int64_t start_offset,
              int64_t number_of_bytes,
              PP_Time expected_last_modified_time);
 
     // Set if the input is a file, false means the |data| is valid.
@@ skipping 100 matching lines @@
 
  private:
   PPB_URLRequestInfo_Data data_;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(URLRequestInfoImpl);
 };
 
 }  // namespace ppapi
 
 #endif  // PPAPI_SHARED_IMPL_URL_REQUEST_INFO_IMPL_H_