Fix dependency: make file_system_util not depend on FileSystemURL

webkit/fileapi/file_system_url.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 WEBKIT_FILEAPI_FILE_SYSTEM_URL_H_
 #define WEBKIT_FILEAPI_FILE_SYSTEM_URL_H_
 
 #include <set>
 #include <string>
 
@@ skipping 104 matching lines @@
     return mount_filesystem_id_;
   }
 
   FileSystemType mount_type() const { return mount_type_; }
 
   std::string DebugString() const;
 
   // Returns true if this URL is a strict parent of the |child|.
   bool IsParent(const FileSystemURL& child) const;
 
+  bool IsInSameFileSystem(const FileSystemURL& other) const;
+
   bool operator==(const FileSystemURL& that) const;
 
   struct WEBKIT_STORAGE_EXPORT Comparator {
     bool operator() (const FileSystemURL& lhs, const FileSystemURL& rhs) const;
   };
 
  private:
   friend class FileSystemContext;
   friend class ExternalMountPoints;
   friend class IsolatedContext;
@@ skipping 27 matching lines @@
   FileSystemType type_;
   base::FilePath path_;
   std::string filesystem_id_;
 };
 
 typedef std::set<FileSystemURL, FileSystemURL::Comparator> FileSystemURLSet;
 
 }  // namespace fileapi
 
 #endif  // WEBKIT_FILEAPI_FILE_SYSTEM_URL_H_