src/vs/editor/common/viewLayout/viewLayout.ts/ViewLayout/getFutureViewport
class ViewLayout:	public getFutureViewport(): Viewport {
		const scrollDimensions = this._scrollable.getScrollDimensions();
		const currentScrollPosition = this._scrollable.getFutureScrollPosition();
		return new Viewport(
			currentScrollPosition.scrollTop,
			currentScrollPosition.scrollLeft,
			scrollDimensions.width,
			scrollDimensions.height
		);
	}