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

compiled/ElemHideBase.h

-#ifndef ADBLOCK_PLUS_ELEM_HIDE_BASE_H
-#define ADBLOCK_PLUS_ELEM_HIDE_BASE_H
+#pragma once
 
 #include <cstddef>
 
 #include "ActiveFilter.h"
 
 struct ElemHideBaseData
 {
   String::size_type mDomainsEnd;
   String::size_type mSelectorStart;
 
   bool HasDomains() const
   {
     return mDomainsEnd != 0;
   }
 
-  String GetDomainsSource(String& text) const
+  DependentString GetDomainsSource(String& text) const
   {
-    return String(text, 0, mDomainsEnd);
+    return DependentString(text, 0, mDomainsEnd);
   }
 
-  const String GetDomainsSource(const String& text) const
+  const DependentString GetDomainsSource(const String& text) const
   {
-    return String(text, 0, mDomainsEnd);
+    return DependentString(text, 0, mDomainsEnd);
   }
 
-  String GetSelector(String& text) const
+  DependentString GetSelector(String& text) const
   {
-    return String(text, mSelectorStart);
+    return DependentString(text, mSelectorStart);
   }
 
-  const String GetSelector(const String& text) const
+  const DependentString GetSelector(const String& text) const
   {
-    return String(text, mSelectorStart);
+    return DependentString(text, mSelectorStart);
   }
 };
 
 struct ElemHideData;
 
-class ElemHideBase : public ActiveFilter, protected ElemHideBaseData
+class ElemHideBase : public ActiveFilter
 {
+protected:
+  ElemHideBaseData mData;
 public:
-  ElemHideBase(const String& text, const ElemHideBaseData& data);
-  static Type Parse(String& text, ElemHideData& data);
+  explicit ElemHideBase(Type type, const String& text, const ElemHideBaseData& data);
+  static Type Parse(DependentString& text, ElemHideData& data);
 
-  EMSCRIPTEN_KEEPALIVE const String GetSelector() const
+  EMSCRIPTEN_KEEPALIVE const DependentString GetSelector() const
   {
-    return ElemHideBaseData::GetSelector(mText);
+    return mData.GetSelector(mText);
   }
 
-  EMSCRIPTEN_KEEPALIVE String GetSelectorDomain() const;
+  EMSCRIPTEN_KEEPALIVE OwnedString GetSelectorDomain() const;
 };
-
-#endif