Include <algorithm> if you use functions from <algorithm>.

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

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 2004-2005 Allan Sandfeld Jensen (kde@carewolf.com)
  * Copyright (C) 2006, 2007 Nicholas Shanks (webkit@nickshanks.com)
  * Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013 Apple Inc. All rights reserved.
  * Copyright (C) 2007 Alexey Proskuryakov <ap@webkit.org>
  * Copyright (C) 2007, 2008 Eric Seidel <eric@webkit.org>
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (c) 2011, Code Aurora Forum. All rights reserved.
  * Copyright (C) Research In Motion Limited 2011. All rights reserved.
@@ skipping 24 matching lines @@
 #include "core/css/CSSRuleList.h"
 #include "core/css/CSSSelector.h"
 #include "core/css/CSSStyleRule.h"
 #include "core/css/CSSStyleSheet.h"
 #include "core/css/CSSSupportsRule.h"
 #include "core/css/StylePropertySet.h"
 #include "core/css/resolver/StyleResolver.h"
 #include "core/css/resolver/StyleResolverStats.h"
 #include "core/dom/shadow/ShadowRoot.h"
 #include "core/style/StyleInheritedData.h"
+#include <algorithm>
 
 namespace blink {
 
 ElementRuleCollector::ElementRuleCollector(const ElementResolveContext& context,
     const SelectorFilter& filter, ComputedStyle* style)
     : m_context(context)
     , m_selectorFilter(filter)
     , m_style(style)
     , m_pseudoStyleRequest(NOPSEUDO)
     , m_mode(SelectorChecker::ResolvingStyle)
@@ skipping 275 matching lines @@
     // should not see the element's treescope. Because RuleSet has no
     // information about "scope".
     MatchRequest matchRequest(ruleSet);
     collectMatchingRules(matchRequest);
     collectMatchingShadowHostRules(matchRequest);
 
     return !m_matchedRules.isEmpty();
 }
 
 } // namespace blink