title: mapFragment.getMapAsync(this) - NullPointerException
body: <p>I am using <code>com.google.android.gms:play-services-maps:7.5.0</code> version of Google Maps services. When trying to call the below I get <code>java.lang.NullPointerException: Attempt to invoke virtual method 'void com.google.android.gms.maps.SupportMapFragment.getMapAsync(com.google.android.gms.maps.OnMapReadyCallback)' on a null object reference</code>.</p>
  
  <pre><code>@Override
  public View onCreateView(LayoutInflater inflater, ViewGroup container,
                           Bundle savedInstanceState) {
      SupportMapFragment mapFragment = (SupportMapFragment) getActivity().getSupportFragmentManager()
              .findFragmentById(R.id.map);
      mapFragment.getMapAsync(this); //error
  
      return inflater.inflate(R.layout.fragment_example_map, container, false);
  }
  </code></pre>
  
  <p>fragment_example_map.xml file:</p>
  
  <pre><code>&lt;FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
      xmlns:tools="http://schemas.android.com/tools"
      android:layout_width="match_parent"
      android:layout_height="match_parent"
      tools:context="app.ExampleMap"&gt;
  
      &lt;fragment xmlns:android="http://schemas.android.com/apk/res/android"
          android:name="com.google.android.gms.maps.SupportMapFragment"
          android:id="@+id/map"
          android:layout_width="match_parent"
          android:layout_height="match_parent"/&gt;
  &lt;/FrameLayout&gt;
  </code></pre>