Desktop aura: Continue threading context through views.

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 127 matching lines @@
       WIDGET_OWNS_NATIVE_WIDGET
     };
 
     InitParams();
     explicit InitParams(Type type);
 
     // If |parent_widget| is non-null, its native view is returned, otherwise
     // |parent| is returned.
     gfx::NativeView GetParent() const;
 
+    // Will return the first of the following that isn't NULL: the native view,
+    // |parent|, |context|.
+    gfx::NativeView GetContext() const;
+
     Type type;
     // If NULL, a default implementation will be constructed.
     WidgetDelegate* delegate;
     bool child;
     bool transient;
     // If true, the widget may be fully or partially transparent.  If false,
     // we can perform optimizations based on the widget being fully opaque.
     // For window widgets, defaults to ViewsDelegate::UseTransparentWindows().
     // Defaults to false for non-window widgets.
     bool transparent;
@@ skipping 653 matching lines @@
 
   // Is |root_layers_| out of date?
   bool root_layers_dirty_;
 
   DISALLOW_COPY_AND_ASSIGN(Widget);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_WIDGET_WIDGET_H_