Java: Add support for callback-based library models.

java/ql/lib/semmle/code/java/dispatch/ObjFlow.qll

@@ -43,8 +43,8 @@ private predicate viableParam(Call call, int i, ParameterNode p) {
  * Holds if `arg` is a possible argument to `p` taking virtual dispatch into account.
  */
 private predicate viableArgParam(ArgumentNode arg, ParameterNode p) {
-  exists(int i, Call call |
-    viableParam(call, i, p) and
+  exists(int i, DataFlowCall call |
+    viableParam(call.asCall(), i, p) and
     arg.argumentOf(call, i)
   )
 }