src/vs/editor/contrib/codelens/codelensWidget.ts/CodeLensViewZone/constructor
class CodeLensViewZone:	constructor(afterLineNumber: number, heightInPx: number, onHeight: () => void) {
		this.afterLineNumber = afterLineNumber;
		this.heightInPx = heightInPx;

		this._onHeight = onHeight;
		this.suppressMouseDown = true;
		this.domNode = document.createElement('div');
	}