Cleanup: Remove unneeded forward declarations in webkit/.

webkit/fileapi/file_system_operation.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 WEBKIT_FILEAPI_FILE_SYSTEM_OPERATION_H_
 #define WEBKIT_FILEAPI_FILE_SYSTEM_OPERATION_H_
 
+#include <string>
 #include <vector>
 
 #include "base/file_path.h"
 #include "base/file_util_proxy.h"
 #include "base/gtest_prod_util.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_callback_factory.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/message_loop_proxy.h"
 #include "base/platform_file.h"
@@ skipping 13 matching lines @@
 }  // namespace net
 
 class GURL;
 
 namespace fileapi {
 
 class FileSystemCallbackDispatcher;
 class FileSystemContext;
 class FileWriterDelegate;
 class FileSystemOperationTest;
-class FileSystemQuotaUtil;
 
 // This class is designed to serve one-time file system operation per instance.
 // Only one method(CreateFile, CreateDirectory, Copy, Move, DirectoryExists,
 // GetMetadata, ReadDirectory and Remove) may be called during the lifetime of
 // this object and it should be called no more than once.
 // This class is self-destructed, or get deleted via base::Owned() fater the
 // operation finishes and completion callback is called.
 class FileSystemOperation {
  public:
   // |dispatcher| will be owned by this class.
@@ skipping 231 matching lines @@
   // write.
   FilePath src_virtual_path_;
   FilePath dest_virtual_path_;
 
   DISALLOW_COPY_AND_ASSIGN(FileSystemOperation);
 };
 
 }  // namespace fileapi
 
 #endif  // WEBKIT_FILEAPI_FILE_SYSTEM_OPERATION_H_