src/vs/workbench/browser/parts/views/viewFilter.ts/FilterWidget/constructor
class FilterWidget:	constructor(
		private readonly options: IFilterWidgetOptions,
		@IInstantiationService private readonly instantiationService: IInstantiationService,
		@IContextViewService private readonly contextViewService: IContextViewService,
		@IThemeService private readonly themeService: IThemeService,
		@IContextKeyService contextKeyService: IContextKeyService,
		@IKeybindingService private readonly keybindingService: IKeybindingService
	) {
		super();
		this.delayedFilterUpdate = new Delayer<void>(400);
		this._register(toDisposable(() => this.delayedFilterUpdate.cancel()));

		if (options.focusContextKey) {
			this.focusContextKey = new RawContextKey(options.focusContextKey, false).bindTo(contextKeyService);
		}

		this.element = DOM.$('.viewpane-filter');
		this.filterInputBox = this.createInput(this.element);

		const controlsContainer = DOM.append(this.element, DOM.$('.viewpane-filter-controls'));
		this.filterBadge = this.createBadge(controlsContainer);
		this.toolbar = this._register(this.createToolBar(controlsContainer));

		this.adjustInputBox();
	}