src/vs/editor/common/viewModel/viewModelImpl.ts/StableViewport/recoverViewportStart
class StableViewport:	public recoverViewportStart(coordinatesConverter: ICoordinatesConverter, viewLayout: ViewLayout): void {
		if (!this.viewportStartModelPosition) {
			return;
		}
		const viewPosition = coordinatesConverter.convertModelPositionToViewPosition(this.viewportStartModelPosition);
		const viewPositionTop = viewLayout.getVerticalOffsetForLineNumber(viewPosition.lineNumber);
		viewLayout.setScrollPosition({ scrollTop: viewPositionTop + this.startLineDelta }, ScrollType.Immediate);
	}