src/vs/editor/browser/viewParts/contentWidgets/contentWidgets.ts/ViewContentWidgets/prepareRender
class ViewContentWidgets:	public prepareRender(ctx: RenderingContext): void {
		const keys = Object.keys(this._widgets);
		for (const widgetId of keys) {
			this._widgets[widgetId].prepareRender(ctx);
		}
	}