Desktop aura: Continue threading context through views.

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 139c69aaab7f32e5f551a2c17aba656d14e267e9..9dbe2d4d45e3bae9e5e705fdaa72fef7f37dd813 100644
--- a/ui/views/widget/widget.h
+++ b/ui/views/widget/widget.h
@@ -145,6 +145,10 @@ class VIEWS_EXPORT Widget : public internal::NativeWidgetDelegate,
     // |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;