Merge pull request #3576 from chenglou/last-getdomnode

Remove last call to `getDOMNode` in tests

src/browser/ui/__tests__/ReactDOMComponent-test.js

@@ -597,7 +597,7 @@ describe('ReactDOMComponent', function() {
       expect(
         ReactBrowserEventEmitter.getListener(rootNodeID, 'onClick')
       ).toBe(callback);
-      expect(rootNode).toBe(instance.getDOMNode());
+      expect(rootNode).toBe(React.findDOMNode(instance));
 
       React.unmountComponentAtNode(container);