diff -r 000000000000 -r 6474c204b198 widget/cocoa/nsChangeObserver.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/widget/cocoa/nsChangeObserver.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,44 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsChangeObserver_h_
+#define nsChangeObserver_h_
+
+class nsIContent;
+class nsIDocument;
+class nsIAtom;
+
+#define NS_DECL_CHANGEOBSERVER \
+void ObserveAttributeChanged(nsIDocument *aDocument, nsIContent *aContent, nsIAtom *aAttribute); \
+void ObserveContentRemoved(nsIDocument *aDocument, nsIContent *aChild, int32_t aIndexInContainer); \
+void ObserveContentInserted(nsIDocument *aDocument, nsIContent* aContainer, nsIContent *aChild);
+
+// Something that wants to be alerted to changes in attributes or changes in
+// its corresponding content object.
+//
+// This interface is used by our menu code so we only have to have one
+// nsIDocumentObserver.
+//
+// Any class that implements this interface must take care to unregister itself
+// on deletion.
+class nsChangeObserver
+{
+public:
+  // XXX use dom::Element
+  virtual void ObserveAttributeChanged(nsIDocument* aDocument,
+                                       nsIContent* aContent,
+                                       nsIAtom* aAttribute)=0;
+
+  virtual void ObserveContentRemoved(nsIDocument* aDocument,
+                                     nsIContent* aChild, 
+                                     int32_t aIndexInContainer)=0;
+
+  virtual void ObserveContentInserted(nsIDocument* aDocument,
+                                      nsIContent* aContainer,
+                                      nsIContent* aChild)=0;
+};
+
+#endif // nsChangeObserver_h_