title: UI-router accessing parent state from child
body: <p>I'd like to set the title based on the state in my angular app. It works nicely, but if there's no title defined on the child state, I'd like to fall back to the parent's title property.</p>
  
  <p>This is what I have so far:</p>
  
  <p><strong>In my app run block:</strong></p>
  
  <pre><code>...
  $rootScope.$on('$stateChangeSuccess', function (event, current, previous) {
  
    if (current.hasOwnProperty('title')) {
      $rootScope.title = current.title;
    }
  });
  ...
  </code></pre>
  
  <p><strong>In my module's route</strong></p>
  
  <pre><code>.state('main.parent', {
    url: '/parent',
    controller: 'ParentController',
    controllerAs: 'vm',
    templateUrl: 'app/parent.html',
    title: 'Parent',
  })
  .state('main.parent.child', {
    url: '/child',
    controller: 'ChildController',
    controllerAs: 'vm',
    templateUrl: 'app/child.html'
  })
  </code></pre>
  
  <p>During the code inspection, I found that <code>$stateChangeSuccess</code> is triggered twice as expected, first for the parent and then for the child. I tried to access <code>current.parent</code> when the child was called, but it has no such property. Is there any way to access it?</p>
  
  <p><strong>UPDATE</strong></p>
  
  <p>I saw these questions:
  <a href="https://stackoverflow.com/q/36864460/2419215">get parent state from ui-router $stateChangeStart</a>,
  <a href="https://stackoverflow.com/questions/36864460/get-parent-state-from-ui-router-statechangestart">get parent state from ui-router $stateChangeStart</a>
  But none of them had a clear answer to this problem (except the state splitting hack in the latter one but I'd rather avoid that).</p>