Allow the Views Delegate to provide the native widget.

ui/views/widget/desktop_native_widget_aura.h

Index: ui/views/widget/desktop_native_widget_aura.h
===================================================================
--- ui/views/widget/desktop_native_widget_aura.h	(revision 156552)
+++ ui/views/widget/desktop_native_widget_aura.h	(working copy)
@@ -20,7 +20,7 @@
   explicit DesktopNativeWidgetAura(internal::NativeWidgetDelegate* delegate);
   virtual ~DesktopNativeWidgetAura();
 
- private:
+ protected:
   // Overridden from internal::NativeWidgetPrivate:
   virtual void InitNativeWidget(const Widget::InitParams& params) OVERRIDE;
   virtual NonClientFrameView* CreateNonClientFrameView() OVERRIDE;
@@ -134,6 +134,7 @@
   virtual ui::TouchStatus OnTouchEvent(ui::TouchEvent* event) OVERRIDE;
   virtual ui::EventResult OnGestureEvent(ui::GestureEvent* event) OVERRIDE;
 
+ private:
   scoped_ptr<DesktopRootWindowHost> desktop_root_window_host_;
   aura::Window* window_;
   Widget::InitParams::Ownership ownership_;