**Do you want to request a *feature* or report a *bug*?**
bug

**What is the current behavior?**
If there is a client/server mismatch for text inside of an a or button element, it causes it to be automatically focused on page load.

**If the current behavior is a bug, please provide the steps to reproduce and if possible a minimal demo of the problem via https://jsfiddle.net or similar (template for React 16: https://jsfiddle.net/Luktwrdm/, template for React 15: https://jsfiddle.net/hmbg7e9w/).**
```
let text;
let URL = '/randomURL';
if (typeof window !== 'undefined') {
  text = 'CLIENT TEXT';
} else {
  text = 'TEXT';
}

return (
  <a href={URL}>
    {text}
  </a>
);
```

if the focus is not on the window (i.e. if a dom element is selected in the chrome inspector or react inspector widnow), then it doesn't add the focus.

**What is the expected behavior?**
The expected behavior is that it would either show CLIENT TEXT or TEXT (depending on how React16 resolves the diff), but for it not to be automatically highlighted 

**Which versions of React, and which browser / OS are affected by this issue? Did this work in previous versions of React?**
React16 / macosx / chrome + ff + safari
render() {
          const staticContent = ReactDOMServer.renderToStaticMarkup(
            <div>
              <img src="foo-bar.jpg" />
            </div>,
          );
          return <div dangerouslySetInnerHTML={{__html: staticContent}} />;
        }
      }
      class Component extends React.Component {
        componentWillMount() {
          this.setState({text: 'hello, world'});
        }
        render() {
          return <div>{this.state.text}</div>;
        }
      }
      expect(
        ReactDOMServer.renderToString.bind(
          ReactDOMServer,
          <div>
            <StaticComponent />
            <Component />
          </div>,
        ),
      ).not.toThrow();
    });
  });
  it('warns with a no-op when an async setState is triggered', () => {
    class Foo extends React.Component {