Allow the Views Delegate to provide the native widget.

ui/views/views_delegate.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef UI_VIEWS_VIEWS_DELEGATE_H_
 #define UI_VIEWS_VIEWS_DELEGATE_H_
 
 #include <string>
 
 #if defined(OS_WIN)
 #include <windows.h>
 #endif
 
 #include "base/string16.h"
 #include "ui/base/accessibility/accessibility_types.h"
 #include "ui/base/ui_base_types.h"
+#include "ui/gfx/native_widget_types.h"
 #include "ui/views/views_export.h"
 
 namespace content {
 class WebContents;
 class BrowserContext;
 class SiteInstance;
 }
 
 namespace gfx {
 class Rect;
 }
 
 namespace views {
 
+class NativeWidget;
 class NonClientFrameView;
 class View;
 class Widget;
-
 #if defined(USE_AURA)
 class NativeWidgetAura;
 class NativeWidgetHelperAura;
 #endif
+namespace internal {
+class NativeWidgetDelegate;
+}
 
 // ViewsDelegate is an interface implemented by an object using the views
 // framework. It is used to obtain various high level application utilities
 // and perform some actions such as window placement saving.
 //
 // The embedding app must set views_delegate to assign its ViewsDelegate
 // implementation.
 class VIEWS_EXPORT ViewsDelegate {
  public:
   // The active ViewsDelegate used by the views system.
@@ skipping 55 matching lines @@
   // Creates an object that implements desktop integration behavior. Returned
   // object is owned by the NativeWidgetAura passed in. May return NULL.
   virtual NativeWidgetHelperAura* CreateNativeWidgetHelper(
       NativeWidgetAura* native_widget) = 0;
 #endif
 
   // Creates a web contents. This will return NULL unless overriden.
   virtual content::WebContents* CreateWebContents(
       content::BrowserContext* browser_context,
       content::SiteInstance* site_instance) = 0;
+
+  // Creates a NativeWidget implementation. Returning NULL means Widget will
+  // create a default implementation for the platform.
+  virtual NativeWidget* CreateNativeWidget(
+      internal::NativeWidgetDelegate* delegate,
+      gfx::NativeView parent) = 0;
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_VIEWS_DELEGATE_H_