Add explicit keyword to constructors that take one argument

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 40 matching lines @@
 
     String name() const { return m_name; }
     void setName(const String& name) { m_name = AtomicString(name); }
 
     int findKeyframeIndex(const String& key) const;
 
     PassRefPtr<StyleRuleKeyframes> copy() const { return adoptRef(new StyleRuleKeyframes(*this)); }
 
 private:
     StyleRuleKeyframes();
-    StyleRuleKeyframes(const StyleRuleKeyframes&);
+    explicit StyleRuleKeyframes(const StyleRuleKeyframes&);
 
     Vector<RefPtr<StyleKeyframe> > m_keyframes;
     AtomicString m_name;
 };
 
 class CSSKeyframesRule : public CSSRule {
 public:
     static PassRefPtr<CSSKeyframesRule> create(StyleRuleKeyframes* rule, CSSStyleSheet* sheet) { return adoptRef(new CSSKeyframesRule(rule, sheet)); }
 
     virtual ~CSSKeyframesRule();
@@ skipping 19 matching lines @@
     CSSKeyframesRule(StyleRuleKeyframes*, CSSStyleSheet* parent);
 
     RefPtr<StyleRuleKeyframes> m_keyframesRule;
     mutable Vector<RefPtr<CSSKeyframeRule> > m_childRuleCSSOMWrappers;
     mutable OwnPtr<CSSRuleList> m_ruleListCSSOMWrapper;
 };
 
 } // namespace WebCore
 
 #endif // CSSKeyframesRule_h