Add an option to specify requested fields for fetching metadata.

storage/browser/fileapi/file_system_operation.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_FILE_SYSTEM_OPERATION_H_
 #define STORAGE_BROWSER_FILEAPI_FILE_SYSTEM_OPERATION_H_
 
 #include <vector>
 
 #include "base/callback.h"
@@ skipping 209 matching lines @@
     // No additional operation.
     OPTION_NONE,
 
     // Preserves last modified time if possible. If the operation to update
     // last modified time is not supported on the file system for the
     // destination file, this option would be simply ignored (i.e. Copy would
     // be successfully done without preserving last modified time).
     OPTION_PRESERVE_LAST_MODIFIED,
   };
 
+  // Fields requested for the GetMetadata method. Used as a bitmask.
+  enum GetMetadataField {
+    GET_METADATA_FIELD_NONE = 0,
+    GET_METADATA_FIELD_SIZE = 1 << 0,
+    GET_METADATA_FIELD_IS_DIRECTORY = 1 << 1,
+    GET_METADATA_FIELD_LAST_MODIFIED = 1 << 2
+  };
+
   // Used for Write().
   typedef base::Callback<void(base::File::Error result,
                               int64 bytes,
                               bool complete)> WriteCallback;
 
   // Creates a file at |path|. If |exclusive| is true, an error is raised
   // in case a file is already present at the URL.
   virtual void CreateFile(const FileSystemURL& path,
                           bool exclusive,
                           const StatusCallback& callback) = 0;
@@ skipping 55 matching lines @@
   // Checks if a directory is present at |path|.
   virtual void DirectoryExists(const FileSystemURL& path,
                                const StatusCallback& callback) = 0;
 
   // Checks if a file is present at |path|.
   virtual void FileExists(const FileSystemURL& path,
                           const StatusCallback& callback) = 0;
 
   // Gets the metadata of a file or directory at |path|.
   virtual void GetMetadata(const FileSystemURL& path,
+                           int fields,
                            const GetMetadataCallback& callback) = 0;
 
   // Reads contents of a directory at |path|.
   virtual void ReadDirectory(const FileSystemURL& path,
                              const ReadDirectoryCallback& callback) = 0;
 
   // Removes a file or directory at |path|. If |recursive| is true, remove
   // all files and directories under the directory at |path| recursively.
   virtual void Remove(const FileSystemURL& path, bool recursive,
                       const StatusCallback& callback) = 0;
@@ skipping 172 matching lines @@
     kOperationOpenFile,
     kOperationCloseFile,
     kOperationGetLocalPath,
     kOperationCancel,
   };
 };
 
 }  // namespace storage
 
 #endif  // STORAGE_BROWSER_FILEAPI_FILE_SYSTEM_OPERATION_H_