Allow menus to stay open during a child view's drag and drop

ui/views/widget/widget.h

Index: ui/views/widget/widget.h
diff --git a/ui/views/widget/widget.h b/ui/views/widget/widget.h
index bc3f91473dd19de5175b0b939a69341424b7a329..0d7ca8a9a57c24489d8fd28ee09cec7a9affb456 100644
--- a/ui/views/widget/widget.h
+++ b/ui/views/widget/widget.h
@@ -793,6 +793,14 @@ class VIEWS_EXPORT Widget : public internal::NativeWidgetDelegate,
   // TODO(beng): remove once we fold those objects onto this one.
   void DestroyRootView();
 
+  // Notification that a drag will start. Default implementation does nothing.
+  virtual void OnDragWillStart();
+
+  // Notification that the drag performed by RunShellDrag() has completed.
+  // |view| is the view that was dragged. This may be NULL.

[sky, 2014/07/14 15:19:05]

I don't think you should pass in view here, it may have been deleted.

[Devlin, 2014/07/16 16:00:45]

Done.

+  // Default implementation does nothing.
+  virtual void OnDragComplete(View* view);
+
  private:
   friend class ComboboxTest;
   friend class TextfieldTest;