title: Hamburger Icon does not show in Navigation Drawer Fragment
body: <p>I am using a Fragement for navigation drawer and hence can't use <code>onPostCreated</code> to call syncState</p>
  
  <pre><code>public class NavigationDrawerFragment extends Fragment{
  ....
  </code></pre>
  
  <p>Calling <code>syncState()</code> on <code>activityCreated</code></p>
  
  <pre><code>@Override
  public void onActivityCreated(Bundle savedInstanceState) {
      super.onActivityCreated(savedInstanceState);
      // Indicate that this fragment would like to influence the set of actions in the action bar.
      setHasOptionsMenu(true);
      mDrawerToggle.syncState();
  }
  </code></pre>
  
  <p>Using the <code>ic_drawer</code> for icon</p>
  
  <pre><code>public void setUp(int fragmentId, DrawerLayout drawerLayout) {
      mFragmentContainerView = getActivity().findViewById(fragmentId);
      mDrawerLayout = drawerLayout;
  
      // set a custom shadow that overlays the main content when the drawer opens
      mDrawerLayout.setDrawerShadow(R.drawable.drawer_shadow, GravityCompat.START);
      // set up the drawer's list view with items and click listener
  
      ActionBar actionBar = getActionBar();
      actionBar.setDisplayHomeAsUpEnabled(true);
      actionBar.setHomeButtonEnabled(true);
  
      // ActionBarDrawerToggle ties together the the proper interactions
      // between the navigation drawer and the action bar app icon.
      mDrawerToggle = new ActionBarDrawerToggle(
              getActivity(),                    /* host Activity */
              mDrawerLayout,                    /* DrawerLayout object */
              R.drawable.ic_drawer,             /* nav drawer image to replace 'Up' caret */
              R.string.navigation_drawer_open,  /* "open drawer" description for accessibility */
              R.string.navigation_drawer_close  /* "close drawer" description for accessibility */
      ) {
          @Override
          public void onDrawerClosed(View drawerView) {
              super.onDrawerClosed(drawerView);
              if (!isAdded()) {
                  return;
              }
  
              getActivity().supportInvalidateOptionsMenu(); // calls onPrepareOptionsMenu()
          }
  
          @Override
          public void onDrawerOpened(View drawerView) {
              super.onDrawerOpened(drawerView);
              if (!isAdded()) {
                  return;
              }
  
              if (!mUserLearnedDrawer) {
                  // The user manually opened the drawer; store this flag to prevent auto-showing
                  // the navigation drawer automatically in the future.
                  mUserLearnedDrawer = true;
                  SharedPreferences sp = PreferenceManager
                          .getDefaultSharedPreferences(getActivity());
                  sp.edit().putBoolean(PREF_USER_LEARNED_DRAWER, true).apply();
              }
  
              getActivity().supportInvalidateOptionsMenu(); // calls onPrepareOptionsMenu()
          }
  
  
      };
  </code></pre>
  
  <p>Can't figure out what is wrong. 
  Please help!</p>