src/vs/editor/browser/viewParts/decorations/decorations.ts/DecorationsOverlay/constructor
class DecorationsOverlay:	constructor(context: ViewContext) {
		super();
		this._context = context;
		const options = this._context.configuration.options;
		this._lineHeight = options.get(EditorOption.lineHeight);
		this._typicalHalfwidthCharacterWidth = options.get(EditorOption.fontInfo).typicalHalfwidthCharacterWidth;
		this._renderResult = null;

		this._context.addEventHandler(this);
	}