Remove stray method declaration in RuleFeatureSet.

third_party/WebKit/Source/core/css/RuleFeature.h

Index: third_party/WebKit/Source/core/css/RuleFeature.h
diff --git a/third_party/WebKit/Source/core/css/RuleFeature.h b/third_party/WebKit/Source/core/css/RuleFeature.h
index 313faead61d4d696456dc3956776719fc4402a6e..4a894ebba1b361316677e6d567a2f1d377cd6345 100644
--- a/third_party/WebKit/Source/core/css/RuleFeature.h
+++ b/third_party/WebKit/Source/core/css/RuleFeature.h
@@ -280,8 +280,6 @@ class CORE_EXPORT RuleFeatureSet {
       const InvalidationSetFeatures& siblingFeatures,
       const InvalidationSetFeatures& descendantFeatures);
 
-  void addClassToInvalidationSet(const AtomicString& className, Element&);
-
   FeatureMetadata m_metadata;
   InvalidationSetMap m_classInvalidationSets;
   InvalidationSetMap m_attributeInvalidationSets;