src/vs/editor/common/viewModel/viewModelImpl.ts/ViewModel/changeWhitespace
class ViewModel:	public changeWhitespace(callback: (accessor: IWhitespaceChangeAccessor) => void): void {
		const hadAChange = this.viewLayout.changeWhitespace(callback);
		if (hadAChange) {
			this._eventDispatcher.emitSingleViewEvent(new viewEvents.ViewZonesChangedEvent());
			this._eventDispatcher.emitOutgoingEvent(new ViewZonesChangedEvent());
		}
	}