+ ASSERT(layoutBox instanceof Layout.Box);
+ return this._mapDisplayMarginBoxToFormattingRoot(this._formattingState().displayBox(layoutBox));
+ }
+
+ _mapDisplayMarginBoxToFormattingRoot(displayBox) {
+ ASSERT(displayBox instanceof Display.Box);
+ return Utils.marginBox(displayBox, this._formattingState().displayBox(this._formattingRoot()));
+ }
+
+ _mapBorderBoxToFormattingRoot(layoutBox) {