In a lot of the WebContentsImplBrowserTests, I see the following pattern:

  LoadStopNotificationObserver load_observer(
      &shell()->web_contents()->GetController());
  NavigateToURL(shell(), embedded_test_server()->GetURL("/title1.html"));
  load_observer.Wait();

For example, here: https://code.google.com/p/chromium/codesearch#chromium/src/content/browser/web_contents/web_contents_impl_browsertest.cc&l=208

It doesn't seem like the observer's Wait() is needed here, since NavigateToURL() already waits for loadstop.