src/vs/workbench/contrib/codeEditor/browser/outline/documentSymbolsOutline.ts/DocumentSymbolsOutline/captureViewState
class DocumentSymbolsOutline:	captureViewState(): IDisposable {
		const viewState = this._editor.saveViewState();
		return toDisposable(() => {
			if (viewState) {
				this._editor.restoreViewState(viewState);
			}
		});
	}