Changes views_aura_mus_unittests to create DesktopNativeWidgetAura

ui/views/test/scoped_views_test_helper.h

Index: ui/views/test/scoped_views_test_helper.h
diff --git a/ui/views/test/scoped_views_test_helper.h b/ui/views/test/scoped_views_test_helper.h
index b3778538204b94b46c0f8da9430b85faa2b01269..bac1de0635ebf3f355d5401f5fc2a5a35f85b59a 100644
--- a/ui/views/test/scoped_views_test_helper.h
+++ b/ui/views/test/scoped_views_test_helper.h
@@ -39,6 +39,10 @@ class ScopedViewsTestHelper {
 
   TestViewsDelegate* views_delegate() { return views_delegate_.get(); };
 
+  PlatformTestHelper* platform_test_helper() {
+    return platform_test_helper_.get();
+  }
+
  private:
   std::unique_ptr<TestViewsDelegate> views_delegate_;
   std::unique_ptr<ViewsTestHelper> test_helper_;