function getAnnouncementForColumn(oColumn, aCells, bIncludeHeader) {
		const oCell = aCells[oColumn.getInitialOrder()];
		let sOutput = ListItemBase.getAccessibilityText(oCell, true);

		if (bIncludeHeader) {
			const oHeader = oColumn.getHeader();
			if (oHeader && oHeader.getVisible()) {
				sOutput = ListItemBase.getAccessibilityText(oHeader) + " " + sOutput;
			}
		}
		return sOutput;
	}
Calculates and returns the bounding client rectangle
of the drop area taking the popin area into account.
@private