When setting boolean attributes on Web Components
`<x-search somebool name={this.props.name} />`
they get rendered as attribute/value pairs instead
`<x-search somebool="true" name={this.props.name}>`

This causes problems with some AMP components, for eg. `<amp-iframe />` which has a `resizable` attribute that gets rendered as `resizable="true"`. This results in non valid AMP content and developers crying with blood tears on their keyboards :)
> The attribute 'resizable' in tag 'amp-iframe' is set to the invalid value 'true'. (see https://www.ampproject.org/docs/reference/components/amp-iframe)

Is there any reason for the current behaviour? Will changing this break something else?
it('allows cased custom attributes', function() {
      let el;
      expect(() => {
        el = ReactTestUtils.renderIntoDocument(<div fooBar="true" />);
      }).toErrorDev(
        'React does not recognize the `fooBar` prop on a DOM element. ' +
          'If you intentionally want it to appear in the DOM as a custom ' +
          'attribute, spell it as lowercase `foobar` instead. ' +
          'If you accidentally passed it from a parent component, remove ' +
          'it from the DOM element.\n' +
          '    in div (at **)',
      );
      expect(el.getAttribute('foobar')).toBe('true');
    });
    it('warns on NaN attributes', function() {
      let el;
      expect(() => {
        el = ReactTestUtils.renderIntoDocument(<div whatever={NaN} />);
      }).toErrorDev(
        'Warning: Received NaN for the `whatever` attribute. If this is ' +
          'expected, cast the value to a string.\n    in div',
      );
      expect(el.getAttribute('whatever')).toBe('NaN');
    });
    it('removes a property when it becomes invalid', function() {
      const container = document.createElement('div');
      ReactDOM.render(<div whatever={0} />, container);
      expect(() =>
        ReactDOM.render(<div whatever={() => {}} />, container),
      ).toErrorDev('Warning: Invalid value for prop `whatever` on <div> tag.');