The error event on `<source>` elements doesn't work. Looking at #4370, it seems like there is an `onError` for `<video>` but I can't tell if that's supposed to work for `<source>` too.

The error event is useful so I can deduce which format the browser is using.

ReactDOM.render(<div style={styles} />, container);
      ReactDOM.render(<div />, container);
      ReactDOM.render(<div style={styles} />, container);
      var stubStyle = container.firstChild.style;
      expect(stubStyle.color).toEqual('red');
    });
    it('should empty element when removing innerHTML', function() {
      var container = document.createElement('div');
      ReactDOM.render(<div dangerouslySetInnerHTML={{__html: ':)'}} />, container);
      expect(container.firstChild.innerHTML).toEqual(':)');
      ReactDOM.render(<div />, container);
      expect(container.firstChild.innerHTML).toEqual('');
    });
    it('should transition from string content to innerHTML', function() {
      var container = document.createElement('div');
      ReactDOM.render(<div>hello</div>, container);
      expect(container.firstChild.innerHTML).toEqual('hello');
      ReactDOM.render(
        <div dangerouslySetInnerHTML={{__html: 'goodbye'}} />,
        container
      );
      expect(container.firstChild.innerHTML).toEqual('goodbye');
    });
    it('should transition from innerHTML to string content', function() {
      var container = document.createElement('div');
      ReactDOM.render(
        <div dangerouslySetInnerHTML={{__html: 'bonjour'}} />,
        container
      );
      expect(container.firstChild.innerHTML).toEqual('bonjour');