Issue 4125 - [emscripten] Convert filter classes to C++

compiled/Filter.h

+#ifndef ADBLOCKPLUS_FILTER_H
+#define ADBLOCKPLUS_FILTER_H
+
+#include <string>
+#include <vector>
+
+class Filter
+{
+private:
+  std::u16string text;
+
+public:
+  Filter(const std::u16string& text);
+
+  /* TODO
+  std::vector<Subscription> subscriptions;
+  */
+
+  const std::u16string get_text() {return text;}
+
+  enum Type
+  {
+    UNKNOWN = 0,
+    INVALID = 1,
+    COMMENT = 2,
+    BLOCKING = 3,
+    WHITELIST = 4,
+    ELEMHIDE = 5,
+    ELEMHIDEEXCEPTION = 6,
+    CSSPROPERTY = 7,
+  };
+
+  virtual Type get_type() = 0;
+
+  virtual const std::u16string Serialize();
+};
+
+#endif