src/vs/workbench/api/common/extHostQuickOpen.ts/ExtHostQuickPick/constructor
class ExtHostQuickPick:		constructor(extension: IExtensionDescription, onDispose: () => void) {
			super(extension.identifier, onDispose);
			this._disposables.push(
				this._onDidChangeActiveEmitter,
				this._onDidChangeSelectionEmitter,
				this._onDidTriggerItemButtonEmitter
			);
			this.update({ type: 'quickPick' });
		}