Minimal Chrome Frame with Aura.

ui/views/widget/widget_observer.h

Index: ui/views/widget/widget_observer.h
diff --git a/ui/views/widget/widget_observer.h b/ui/views/widget/widget_observer.h
index 42f45b3d658b3f9caa70966b6d3cf7c7e4f6bf19..e156ef80c88ae07b7d79f733e3a6f6b895e96863 100644
--- a/ui/views/widget/widget_observer.h
+++ b/ui/views/widget/widget_observer.h
@@ -23,11 +23,19 @@ class VIEWS_EXPORT WidgetObserver {
   // CloseNow()).
   virtual void OnWidgetClosing(Widget* widget) {}
 
+  // Invoked after notification is received from the event loop that the native
+  // widget has been created.
+  virtual void OnWidgetCreated(Widget* widget) {}
+
   // The destroying event occurs immediately before the widget is destroyed.
   // This typically occurs asynchronously with respect the the close request, as
   // a result of a later invocation from the event loop.
   virtual void OnWidgetDestroying(Widget* widget) {}
 
+  // Invoked after notification is received from the event loop that the native
+  // widget has been destroyed.
+  virtual void OnWidgetDestroyed(Widget* widget) {}
+
   virtual void OnWidgetVisibilityChanged(Widget* widget, bool visible) {}
 
   virtual void OnWidgetActivationChanged(Widget* widget, bool active) {}