Migrate WTF::HashSet::add() to ::insert() [part 1 of N]

third_party/WebKit/Source/core/css/resolver/ScopedStyleResolver.cpp

 /*
  * 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) 2012 Google 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
@@ skipping 98 matching lines @@
         visitedSharedStyleSheetContents) const {
   features.viewportDependentMediaQueryResults().appendVector(
       m_viewportDependentMediaQueryResults);
   features.deviceDependentMediaQueryResults().appendVector(
       m_deviceDependentMediaQueryResults);
 
   for (size_t i = 0; i < m_authorStyleSheets.size(); ++i) {
     ASSERT(m_authorStyleSheets[i]->ownerNode());
     StyleSheetContents* contents = m_authorStyleSheets[i]->contents();
     if (contents->hasOneClient() ||
-        visitedSharedStyleSheetContents.add(contents).isNewEntry)
+        visitedSharedStyleSheetContents.insert(contents).isNewEntry)
       features.add(contents->ruleSet().features());
   }
 
   if (!m_treeBoundaryCrossingRuleSet)
     return;
 
   for (const auto& rules : *m_treeBoundaryCrossingRuleSet)
     features.add(rules->m_ruleSet->features());
 }
 
@@ skipping 189 matching lines @@
   }
   return true;
 }
 
 DEFINE_TRACE(ScopedStyleResolver::RuleSubSet) {
   visitor->trace(m_parentStyleSheet);
   visitor->trace(m_ruleSet);
 }
 
 }  // namespace blink