title: Are NavigationTiming properties available in UserTiming measure?
body: <p>Is it possible to use the NavigationTiming properties when using <code>measure</code> in the UserTiming API?</p>
  
  <p>In other words, is the following according to spec?</p>
  
  <pre><code>window.performance.mark('foo');
  window.performance.measure('myMeasurement', 'fetchStart', 'foo');
  </code></pre>
  
  <p>The <a href="http://www.w3.org/TR/user-timing/#dom-performance-measure" rel="nofollow">UserTiming spec</a> states that the NavigationTiming properties are reserved when calling <code>mark</code>, and it seems to behave that way when I experiment in the console.</p>
  
  <p>However, I can't find anything in the spec which states this is the expected behavior. Anyone know?</p>