src/vs/editor/common/viewEvents.ts/ViewScrollChangedEvent/constructor
class ViewScrollChangedEvent:	constructor(source: ScrollEvent) {
		this.scrollWidth = source.scrollWidth;
		this.scrollLeft = source.scrollLeft;
		this.scrollHeight = source.scrollHeight;
		this.scrollTop = source.scrollTop;

		this.scrollWidthChanged = source.scrollWidthChanged;
		this.scrollLeftChanged = source.scrollLeftChanged;
		this.scrollHeightChanged = source.scrollHeightChanged;
		this.scrollTopChanged = source.scrollTopChanged;
	}