Refactor RuleFeatureSet to simplify iteration over CSS Selectors when collecting data.

Source/core/css/resolver/StyleResolver.cpp

Index: Source/core/css/resolver/StyleResolver.cpp
diff --git a/Source/core/css/resolver/StyleResolver.cpp b/Source/core/css/resolver/StyleResolver.cpp
index eeaac0a9ae34a938d36d89f7e57ee922f0f1d550..b8606c56b8ee10d027c3f24761274f5b2376feeb 100644
--- a/Source/core/css/resolver/StyleResolver.cpp
+++ b/Source/core/css/resolver/StyleResolver.cpp
@@ -333,7 +333,7 @@ void StyleResolver::collectFeatures()
 
 bool StyleResolver::hasRulesForId(const AtomicString& id) const
 {
-    return m_features.idsInRules.contains(id);
+    return m_features.hasSelectorForId(id);
 }
 
 void StyleResolver::addToStyleSharingList(Element& element)
@@ -628,7 +628,7 @@ static inline void resetDirectionAndWritingModeOnDocument(Document& document)
 static void addContentAttrValuesToFeatures(const Vector<AtomicString>& contentAttrValues, RuleFeatureSet& features)
 {
     for (size_t i = 0; i < contentAttrValues.size(); ++i)
-        features.attrsInRules.add(contentAttrValues[i]);
+        features.addAttributeInASelector(contentAttrValues[i]);
 }
 
 PassRefPtr<RenderStyle> StyleResolver::styleForElement(Element* element, RenderStyle* defaultParent, StyleSharingBehavior sharingBehavior,