src/vs/editor/browser/config/charWidthReader.ts/DomCharWidthReader/constructor
class DomCharWidthReader:	constructor(bareFontInfo: BareFontInfo, requests: CharWidthRequest[]) {
		this._bareFontInfo = bareFontInfo;
		this._requests = requests;

		this._container = null;
		this._testElements = null;
	}