src/vs/base/browser/ui/grid/grid.ts/Grid/addViewAt
class Grid:	private addViewAt(newView: T, size: number | DistributeSizing | InvisibleSizing, location: GridLocation): void {
		if (this.views.has(newView)) {
			throw new Error('Can\'t add same view twice');
		}

		let viewSize: number | GridViewSizing;

		if (typeof size === 'number') {
			viewSize = size;
		} else if (size.type === 'distribute') {
			viewSize = GridViewSizing.Distribute;
		} else {
			viewSize = size;
		}

		this._addView(newView, viewSize, location);
	}