gdata: Add GDataFileSystem::ReadDirectoryByPathAsync()

chrome/browser/chromeos/gdata/mock_gdata_file_system.h

Index: chrome/browser/chromeos/gdata/mock_gdata_file_system.h
diff --git a/chrome/browser/chromeos/gdata/mock_gdata_file_system.h b/chrome/browser/chromeos/gdata/mock_gdata_file_system.h
index 37db08886a3c809c43f4206803d71407646b782f..b21fe9b6edd58f7af042665f6e4663318edd34a3 100644
--- a/chrome/browser/chromeos/gdata/mock_gdata_file_system.h
+++ b/chrome/browser/chromeos/gdata/mock_gdata_file_system.h
@@ -63,6 +63,9 @@ class MockGDataFileSystem : public GDataFileSystemInterface {
   MOCK_METHOD2(GetFileInfoByPathAsync,
                void(const FilePath& file_path,
                     const GetFileInfoCallback& callback));
+  MOCK_METHOD2(ReadDirectoryByPathAsync,
+               void(const FilePath& file_path,
+                    const ReadDirectoryCallback& callback));
   MOCK_METHOD2(GetFileInfoByPath, bool(const FilePath& file_path,
                                        GDataFileProperties* properties));
   MOCK_CONST_METHOD1(IsUnderGDataCacheDirectory, bool(const FilePath& path));