Scopeless matching of :host rules for style sharing.

third_party/WebKit/Source/core/css/resolver/MatchRequest.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc.
  * All rights reserved.
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
@@ skipping 18 matching lines @@
 
 namespace blink {
 
 class ContainerNode;
 
 class MatchRequest {
   STACK_ALLOCATED();
 
  public:
   MatchRequest(RuleSet* rule_set,
-               const ContainerNode* scope = 0,
-               const CSSStyleSheet* css_sheet = 0,
+               const ContainerNode* scope = nullptr,
+               const CSSStyleSheet* css_sheet = nullptr,
                unsigned style_sheet_index = 0)
       : rule_set(rule_set),
         scope(scope),
         style_sheet(css_sheet),
         style_sheet_index(style_sheet_index) {
     // Now that we're about to read from the RuleSet, we're done adding more
     // rules to the set and we should make sure it's compacted.
     rule_set->CompactRulesIfNeeded();
   }
 
   Member<const RuleSet> rule_set;
   Member<const ContainerNode> scope;
   Member<const CSSStyleSheet> style_sheet;
   const unsigned style_sheet_index;
 };
 
 }  // namespace blink
 
 #endif  // MatchRequest_h