FileSystem: Modify ObfucatedFileUtil to delete contents of the plugin private filesystem

storage/browser/fileapi/obfuscated_file_util.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 STORAGE_BROWSER_FILEAPI_OBFUSCATED_FILE_UTIL_H_
 #define STORAGE_BROWSER_FILEAPI_OBFUSCATED_FILE_UTIL_H_
 
 #include <map>
 #include <set>
 #include <string>
@@ skipping 179 matching lines @@
       const GURL& origin,
       const std::string& type_string);
 
   // This method and all methods of its returned class must be called only on
   // the FILE thread.  The caller is responsible for deleting the returned
   // object.
   AbstractOriginEnumerator* CreateOriginEnumerator();
 
   // Deletes a directory database from the database list in the ObfuscatedFSFU
   // and destroys the database on the disk.
-  bool DestroyDirectoryDatabase(const GURL& origin,
+  void DestroyDirectoryDatabase(const GURL& origin,
                                 const std::string& type_string);
 
   // Computes a cost for storing a given file in the obfuscated FSFU.
   // As the cost of a file is independent of the cost of its parent directories,
   // this ignores all but the BaseName of the supplied path.  In order to
   // compute the cost of adding a multi-segment directory recursively, call this
   // on each path segment and add the results.
   static int64 ComputeFilePathCost(const base::FilePath& path);
 
   // Tries to prepopulate directory database for the given type strings.
@@ skipping 129 matching lines @@
 
   // Not owned.
   SandboxFileSystemBackendDelegate* sandbox_delegate_;
 
   DISALLOW_COPY_AND_ASSIGN(ObfuscatedFileUtil);
 };
 
 }  // namespace storage
 
 #endif  // STORAGE_BROWSER_FILEAPI_OBFUSCATED_FILE_UTIL_H_