Bug 394042 - "Dangling pointer in nsXULPDGlobalObject leads to mem corruption/crash". r+sr+a=jst.

content/xul/document/src/nsXULPrototypeDocument.cpp

@@ -766,6 +766,7 @@ nsXULPDGlobalObject::ClearGlobalObjectOwner()
             mScriptContexts[lang_ndx] = nsnull;
         }
     }
+    mGlobalObjectOwner = nsnull;
 }