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

compiled/CSSPropertyFilter.h

-#ifndef ADBLOCK_PLUS_CSS_PROPERTY_FILTER_H
-#define ADBLOCK_PLUS_CSS_PROPERTY_FILTER_H
+#pragma once
 
 #include <cstddef>
 
 #include "Filter.h"
 #include "ElemHideBase.h"
 
 struct CSSPropertyFilterData
 {
   String::size_type mPrefixEnd;
   String::size_type mRegexpStart;
   String::size_type mRegexpEnd;
   String::size_type mSuffixStart;
 
-  const String GetSelectorPrefix(const String& text,
+  const DependentString GetSelectorPrefix(const String& text,
       String::size_type selectorStart) const
   {
-    return String(text, selectorStart, mPrefixEnd - selectorStart);
+    return DependentString(text, selectorStart, mPrefixEnd - selectorStart);
   }
 
-  const String GetRegExpSource(const String& text) const
+  const DependentString GetRegExpSource(const String& text) const
   {
-    return String(text, mRegexpStart, mRegexpEnd - mRegexpStart);
+    return DependentString(text, mRegexpStart, mRegexpEnd - mRegexpStart);
   }
 
-  const String GetSelectorSuffix(const String& text) const
+  const DependentString GetSelectorSuffix(const String& text) const
   {
-    return String(text, mSuffixStart);
+    return DependentString(text, mSuffixStart);
   }
 };
 
 struct ElemHideData : ElemHideBaseData, CSSPropertyFilterData
 {
 };
 
-class CSSPropertyFilter: public ElemHideBase, protected CSSPropertyFilterData
+class CSSPropertyFilter: public ElemHideBase
 {
+protected:
+  CSSPropertyFilterData mPropertyData;
 public:
-  CSSPropertyFilter(const String& text, const ElemHideData& data);
-  Type GetType() const;
-  EMSCRIPTEN_KEEPALIVE String GetRegExpString() const;
-  EMSCRIPTEN_KEEPALIVE const String GetSelectorPrefix() const
+  explicit CSSPropertyFilter(const String& text, const ElemHideData& data);
+  EMSCRIPTEN_KEEPALIVE OwnedString GetRegExpString() const;
+  EMSCRIPTEN_KEEPALIVE const DependentString GetSelectorPrefix() const
   {
-    return CSSPropertyFilterData::GetSelectorPrefix(mText, mSelectorStart);
+    return mPropertyData.GetSelectorPrefix(mText, mData.mSelectorStart);
   }
-  EMSCRIPTEN_KEEPALIVE const String GetSelectorSuffix() const
+  EMSCRIPTEN_KEEPALIVE const DependentString GetSelectorSuffix() const
   {
-    return CSSPropertyFilterData::GetSelectorSuffix(mText);
+    return mPropertyData.GetSelectorSuffix(mText);
   }
 };
-
-#endif