Bug 376013 [a11y]Incorrect text information sent in "object:text-changed:insert" events.

patch by Evan.Yan at sun.com r=aaronleventhal

accessible/src/html/nsHyperTextAccessible.cpp

@@ -1185,7 +1185,9 @@ NS_IMETHODIMP nsHyperTextAccessible::DidInsertNode(nsIDOMNode *aNode, nsIDOMNode
     }
   }
 
-  if (NS_FAILED(DOMPointToOffset(aNode, aPosition, &start)))
+  nsCOMPtr<nsIDOMNode> parentNode;
+  aNode->GetParentNode(getter_AddRefs(parentNode));
+  if (NS_FAILED(DOMPointToOffset(parentNode, aPosition, &start)))
     return NS_OK;
 
   nsCOMPtr<nsIAccessibleTextChangeEvent> event =