Issue 4127 - [emscripten] Convert subscription classes to C++ - Part 2

compiled/subscription/UserDefinedSubscription.h

 #pragma once
 
 #include "Subscription.h"
 #include "../filter/Filter.h"
 
 class UserDefinedSubscription : public Subscription
 {
 private:
   enum Defaults
   {
     WHITELIST = 1,
     BLOCKING = 2,
     ELEMHIDE = 4,
   };
   static int filterTypeToDefaults[Filter::Type::MAXTYPE + 1];
   int mDefaults;
 
 public:
   explicit UserDefinedSubscription(const String& id);
   EMSCRIPTEN_KEEPALIVE bool IsDefaultFor(const Filter* filter) const;
   EMSCRIPTEN_KEEPALIVE void MakeDefaultFor(const Filter* filter);
+  EMSCRIPTEN_KEEPALIVE void InsertFilterAt(Filter* filter, unsigned pos);
+  EMSCRIPTEN_KEEPALIVE bool RemoveFilterAt(unsigned pos);
   EMSCRIPTEN_KEEPALIVE OwnedString Serialize() const;
 };