JS: Track trusted type policy callbacks

Author: asgerf

javascript/ql/lib/semmle/javascript/frameworks/TrustedTypes.qll

@@ -25,8 +25,7 @@ module TrustedTypes {
 
     /** Gets the function passed as the given option. */
     DataFlow::FunctionNode getPolicyCallback(string method) {
-      // Require local callback to avoid potential call/return mismatch in the uses below
-      result = getOptionArgument(1, method).getALocalSource()
+      result = getParameter(1).getMember(method).getAValueReachingSink()
     }
   }