Bug 1445396 - remove nsIDOMText use in chat. r=florian

chat/modules/imContentSink.jsm

@@ -340,7 +340,8 @@ function cleanupNode(aNode, aRules, aTextModifiers)
           // If we are processing nodes created by one of the previous
           // text modifier function, some of the nodes are likely not
           // text node, skip them.
-          if (!(textNode instanceof Ci.nsIDOMText))
+          if (textNode.nodeType != textNode.TEXT_NODE &&
+              textNode.nodeType != textNode.CDATA_SECTION_NODE)
             continue;
 
           let result = modifier(textNode);

chat/modules/imSmileys.jsm

@@ -210,7 +210,8 @@ function smileNode(aNode)
         node.namespaceURI == "http://www.w3.org/1999/xhtml") {
       // we are on a tag, recurse to process its children
       smileNode(node);
-    } else if (node instanceof Ci.nsIDOMText) {
+    } else if (node.nodeType == node.TEXT_NODE ||
+               node.nodeType == node.CDATA_SECTION_NODE) {
       // we are on a text node, process it
       smileTextNode(node);
     }