Fixes focus traversal bug

ui/views/widget/widget.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_WIDGET_WIDGET_H_
 #define UI_VIEWS_WIDGET_WIDGET_H_
 
 #include <set>
 #include <stack>
 #include <vector>
@@ skipping 746 matching lines @@
 
   // Sets a different InputMethod instance to this widget. The instance
   // must not be initialized, the ownership will be assumed by the widget.
   // It's only for testing purpose.
   void ReplaceInputMethod(InputMethod* input_method);
 
   internal::NativeWidgetPrivate* native_widget_;
 
   ObserverList<WidgetObserver> observers_;
 
-  // Non-owned pointer to the Widget's delegate.  May be NULL if no delegate is
-  // being used.
+  // Non-owned pointer to the Widget's delegate. If a NULL delegate is supplied
+  // to Init() a default WidgetDelegate is created.
   WidgetDelegate* widget_delegate_;
 
   // The root of the View hierarchy attached to this window.
   // WARNING: see warning in tooltip_manager_ for ordering dependencies with
   // this and tooltip_manager_.
   scoped_ptr<internal::RootView> root_view_;
 
   // The View that provides the non-client area of the window (title bar,
   // window controls, sizing borders etc). To use an implementation other than
   // the default, this class must be sub-classed and this value set to the
@@ skipping 77 matching lines @@
   // True when window movement via mouse interaction with the frame should be
   // disabled.
   bool movement_disabled_;
 
   DISALLOW_COPY_AND_ASSIGN(Widget);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_WIDGET_WIDGET_H_