Make CSSKeyframesRule.insertRule an alias of appendRule

Source/core/css/CSSKeyframesRule.h

 /*
  * Copyright (C) 2007, 2008, 2012 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 76 matching lines @@
     virtual ~CSSKeyframesRule();
 
     virtual String cssText() const override;
     virtual void reattach(StyleRuleBase*) override;
 
     String name() const { return m_keyframesRule->name(); }
     void setName(const String&);
 
     CSSRuleList* cssRules();
 
-    void insertRule(const String& rule);
+    void appendRule(const String& rule);
     void deleteRule(const String& key);
     CSSKeyframeRule* findRule(const String& key);
 
     // For IndexedGetter and CSSRuleList.
     unsigned length() const;
     CSSKeyframeRule* item(unsigned index) const;
 
     bool isVendorPrefixed() const { return m_isPrefixed; }
     void setVendorPrefixed(bool isPrefixed) { m_isPrefixed = isPrefixed; }
 
@@ skipping 10 matching lines @@
     mutable WillBeHeapVector<RefPtrWillBeMember<CSSKeyframeRule>> m_childRuleCSSOMWrappers;
     mutable OwnPtrWillBeMember<CSSRuleList> m_ruleListCSSOMWrapper;
     bool m_isPrefixed;
 };
 
 DEFINE_CSS_RULE_TYPE_CASTS(CSSKeyframesRule, KEYFRAMES_RULE);
 
 } // namespace blink
 
 #endif // CSSKeyframesRule_h