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

storage/browser/fileapi/obfuscated_file_util.h

Index: storage/browser/fileapi/obfuscated_file_util.h
diff --git a/storage/browser/fileapi/obfuscated_file_util.h b/storage/browser/fileapi/obfuscated_file_util.h
index 822a85d11d83eca6b00a78dc59fb8219b1ff841f..b8e88171e9720a454f5534119320039641fd4a6f 100644
--- a/storage/browser/fileapi/obfuscated_file_util.h
+++ b/storage/browser/fileapi/obfuscated_file_util.h
@@ -200,6 +200,11 @@ class STORAGE_EXPORT_PRIVATE ObfuscatedFileUtil
       const GURL& origin,
       const std::string& type_string);
 
+  // Deletes all files and directories in all plugin private filesystems
+  // associated with |origin|.  And also deletes their directory databases from
+  // the database list.
+  bool DeleteOriginDirectoryForPluginPrivateFileSystem(const GURL& origin);
+
   // 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.