views: add harmony control label alignment

ui/views/layout/layout_constants.h

Index: ui/views/layout/layout_constants.h
diff --git a/ui/views/layout/layout_constants.h b/ui/views/layout/layout_constants.h
index 2694d9c916b6f8eb32a69c50088d545c279c8213..84cef5179f66376ab91c11c2d28dae879e128213 100644
--- a/ui/views/layout/layout_constants.h
+++ b/ui/views/layout/layout_constants.h
@@ -80,9 +80,6 @@ const int kCheckboxIndent = 10;
 // and the start of its corresponding text.
 const int kItemLabelSpacing = 10;
 
-// Horizontal alignment used for a control's introductory label in a GridLayout.
-const GridLayout::Alignment kControlLabelGridAlignment = GridLayout::LEADING;
-
 }  // namespace views
 
 #endif  // UI_VIEWS_LAYOUT_LAYOUT_CONSTANTS_H_