title: Flutter global material localizations and initialize date formatting not working together
body: <p>I am using localisation in a flutter app but also want to localise the date format using initialise date formatting. My main looks like this ...</p>
  
  <pre><code>  void main() {
      runApp(new MaterialApp(
      supportedLocales:
      [const Locale('en', 'US'),
      const Locale('en', 'AU')],
      localizationsDelegates: [
        const DemoLocalizationsDelegate(),
        GlobalMaterialLocalizations.delegate,
        GlobalWidgetsLocalizations.delegate
      ],
      home: new ThirdPageWidget(),
      navigatorObservers: [routeObserver],
      ));
   }
  </code></pre>
  
  <p>Also I have a initializeDateFormatting in a stateful widget like this ...</p>
  
  <pre><code>@override
  void initState() {
     super.initState();
     initializeDateFormatting().then((_) {
        dateFormat = new DateFormat.yMd('en_AU');
        print(dateFormat.format(DateTime.now()));
  });
  </code></pre>
  
  <p>Now when the locale is en_AU the format of the date is month/day/year american style but when I remove this line of code</p>
  
  <pre><code>GlobalMaterialLocalizations.delegate,
  </code></pre>
  
  <p>The date correctly displays day/month/year. Does any one know what I can do to fix this? How important is it to have the GlobalMaterialLocalizations.delegate?</p>