Part 2 of fix for bug 533401 (Names added through external DOM classinfo don't resolve on global object). r=jst, a=beltzner.

dom/base/nsDOMClassInfo.cpp

@@ -5509,7 +5509,7 @@ private:
 
   static PRBool IsConstructable(const nsDOMClassInfoData *aData)
   {
-    if (IS_EXTERNAL(aData)) {
+    if (IS_EXTERNAL(aData->mCachedClassInfo)) {
       const nsExternalDOMClassInfoData* data =
         static_cast<const nsExternalDOMClassInfoData*>(aData);
       return data->mConstructorCID != nsnull;