V2 app support step2 : Use NativeAppWindow for Activity's window.

athena/activity/public/activity_view_model.h

 // Copyright 2014 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 ATHENA_ACTIVITY_PUBLIC_ACTIVITY_VIEW_MODEL_H_
 #define ATHENA_ACTIVITY_PUBLIC_ACTIVITY_VIEW_MODEL_H_
 
 #include "athena/athena_export.h"
 #include "base/strings/string16.h"
 
 typedef unsigned int SkColor;
 
 namespace gfx {
 class ImageSkia;
 }
 
 namespace views {
 class View;
+class Widget;
 }
 
 namespace athena {
 
 // The view model for the representation of the activity.
 class ATHENA_EXPORT ActivityViewModel {
  public:
   virtual ~ActivityViewModel() {}
 
   // Called after the view model is attached to the widget/window tree and
@@ skipping 10 matching lines @@
 
   // True if the activity wants to use Widget's frame, or false if the activity
   // draws its own frame.
   virtual bool UsesFrame() const = 0;
 
   // Returns the contents view which might be NULL if the activity is not
   // loaded. Note that the caller should not hold on to the view since it can
   // be deleted by the resource manager.
   virtual views::View* GetContentsView() = 0;
 
+  // Creates a custom widget for the activity. Returns NULL to use default
+  // implementation.
+  virtual views::Widget* CreateWidget() = 0;
+
   // This gets called before the Activity gets (partially) thrown out of memory
   // to create a preview image of the activity. Note that even if this function
   // gets called, |GetOverviewModeImage()| could still return an empty image.
   virtual void CreateOverviewModeImage() = 0;
 
   // Returns an image which can be used to represent the activity in e.g. the
   // overview mode. The returned image can have no size if either a view exists
   // or the activity has not yet been loaded. In that case
   // GetRepresentativeColor() should be used to clear the preview area.
   // Note: We intentionally do not use a layer / view for this.
   virtual gfx::ImageSkia GetOverviewModeImage() = 0;
 
   // Prepares the contents view for overview.
   virtual void PrepareContentsForOverview() = 0;
 
   // Undoes any changes done by PrepareContentsForOverview().
   virtual void ResetContentsView() = 0;
 };
 
 }  // namespace athena
 
 #endif  // ATHENA_ACTIVITY_PUBLIC_ACTIVITY_VIEW_MODEL_H_