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

compiled/CommentFilter.cpp

 #include "CommentFilter.h"
 
-CommentFilter::CommentFilter(const std::u16string& text)
-    : Filter(text)
+CommentFilter::CommentFilter(const String& text)
+    : Filter(Type::COMMENT, text)
 {
 }
 
-Filter::Type CommentFilter::Parse(const std::u16string& text)
+Filter::Type CommentFilter::Parse(const String& text)
 {
   if (text.length() && text[0] == u'!')
     return Type::COMMENT;
   else
     return Type::UNKNOWN;
 }
 
-CommentFilter* CommentFilter::Create(const std::u16string& text)
+CommentFilter* CommentFilter::Create(const String& text)
 {
   Type type = Parse(text);
   if (type == Type::COMMENT)
     return new CommentFilter(text);
   else
     return nullptr;
 }
-
-Filter::Type CommentFilter::GetType() const
-{
-  return Type::COMMENT;
-}