Backend for css rule tracking

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

Index: third_party/WebKit/Source/core/css/ElementRuleCollector.h
diff --git a/third_party/WebKit/Source/core/css/ElementRuleCollector.h b/third_party/WebKit/Source/core/css/ElementRuleCollector.h
index a33d09b4443450f0f6b7d546d020e79bacfe1ce2..c2c7dca769d21f481f6707bede32933b08f2f77c 100644
--- a/third_party/WebKit/Source/core/css/ElementRuleCollector.h
+++ b/third_party/WebKit/Source/core/css/ElementRuleCollector.h
@@ -40,6 +40,7 @@ class RuleData;
 class RuleSet;
 class SelectorFilter;
 class StaticCSSRuleList;
+class StyleRuleUsageTracker;
 
 // TODO(kochi): CascadeOrder is used only for Shadow DOM V0 bug-compatible
 // cascading order. Once Shadow DOM V0 implementation is gone, remove this
@@ -143,6 +144,8 @@ class ElementRuleCollector {
     return m_pseudoStyleRequest.pseudoId != PseudoIdNone;
   }
 
+  void addMatchedRulesToTracker(StyleRuleUsageTracker*) const;
+
  private:
   template <typename RuleDataListType>
   void collectMatchingRulesForList(const RuleDataListType*,