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

Source/core/dom/Element.h

Index: Source/core/dom/Element.h
diff --git a/Source/core/dom/Element.h b/Source/core/dom/Element.h
index d2ad8caf1afb56e95a2bf702f5fe8e90dfe055ef..a8f761fd078d877cf073625f5f2be7823a5d7c9f 100644
--- a/Source/core/dom/Element.h
+++ b/Source/core/dom/Element.h
@@ -309,6 +309,8 @@ public:
     void setAnimationStyleChange(bool);
     void setNeedsAnimationStyleRecalc();
 
+    bool needsInvalidation() const;
+
     bool supportsStyleSharing() const;
 
     ElementShadow* shadow() const;
@@ -546,6 +548,13 @@ protected:
         RELEASE_ASSERT(document);
     }
 
+    template<typename Checker>
+    bool checkSelectorForClassChange(const SpaceSplitString& changedClasses, const Checker&);
+
+    template<typename Checker>
+    bool checkSelectorForClassChange(const SpaceSplitString& oldClasses, const SpaceSplitString& newClasses, const Checker&);
+
+
     void addPropertyToPresentationAttributeStyle(MutableStylePropertySet*, CSSPropertyID, CSSValueID identifier);
     void addPropertyToPresentationAttributeStyle(MutableStylePropertySet*, CSSPropertyID, double value, CSSPrimitiveValue::UnitTypes);
     void addPropertyToPresentationAttributeStyle(MutableStylePropertySet*, CSSPropertyID, const String& value);