Add a first pass of a class descendant invalidator, and a containing RuleSetAnalyzer

Source/core/css/RuleFeature.h

Index: Source/core/css/RuleFeature.h
diff --git a/Source/core/css/RuleFeature.h b/Source/core/css/RuleFeature.h
index b51863c428975a72a41f1295c091d558f12976a3..72685af2e7170a985cc37ec5afbb45f5199c34e6 100644
--- a/Source/core/css/RuleFeature.h
+++ b/Source/core/css/RuleFeature.h
@@ -22,6 +22,7 @@
 #ifndef RuleFeature_h
 #define RuleFeature_h
 
+#include "core/css/analyzer/RuleSetAnalyzer.h"
 #include "wtf/Forward.h"
 #include "wtf/HashSet.h"
 #include "wtf/text/AtomicStringHash.h"
@@ -54,7 +55,7 @@ public:
     void add(const RuleFeatureSet&);
     void clear();
 
-    void collectFeaturesFromSelector(const CSSSelector*);
+    void collectFeaturesFromSelector(const CSSSelector*, HashSet<AtomicString>* classesInRulesArg);
 
     bool usesSiblingRules() const { return !siblingRules.isEmpty(); }
     bool usesFirstLineRules() const { return m_usesFirstLineRules; }
@@ -80,13 +81,19 @@ public:
         return idsInRules.contains(idValue);
     }
 
+    RuleSetAnalyzer* getRuleSetAnalyzer() const;
+    RuleSetAnalyzer* ensureRuleSetAnalyzer();
+
+    // FIXME: move this stuff into the rule set analyzer.
     HashSet<AtomicString> idsInRules;
     HashSet<AtomicString> classesInRules;
     HashSet<AtomicString> attrsInRules;
     Vector<RuleFeature> siblingRules;
     Vector<RuleFeature> uncommonAttributeRules;
 private:
-    void collectFeaturesFromSelectorList(const CSSSelectorList*);
+    RefPtr<RuleSetAnalyzer> ruleSetAnalyzer;
+
+    void collectFeaturesFromSelectorList(const CSSSelectorList*, HashSet<AtomicString>* classesInRulesArg);
 
     bool m_usesFirstLineRules;
     unsigned m_maxDirectAdjacentSelectors;