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

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

 /*
  * Copyright (C) 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 20 matching lines @@
 #include "core/dom/Document.h"
 #include "core/fetch/FetchInitiatorTypeNames.h"
 #include "core/fetch/FetchRequest.h"
 #include "core/fetch/ImageResource.h"
 #include "core/fetch/ResourceFetcher.h"
 #include "core/fetch/ResourceLoaderOptions.h"
 #include "core/style/StyleFetchedImageSet.h"
 #include "platform/weborigin/KURL.h"
 #include "platform/weborigin/SecurityPolicy.h"
 #include "wtf/text/StringBuilder.h"
+#include <algorithm>
 
 namespace blink {
 
 CSSImageSetValue::CSSImageSetValue()
     : CSSValueList(ImageSetClass, CommaSeparator)
     , m_isCachePending(true)
     , m_cachedScaleFactor(1)
 {
 }
 
@@ skipping 129 matching lines @@
 PassRefPtrWillBeRawPtr<CSSImageSetValue> CSSImageSetValue::valueWithURLsMadeAbsolute()
 {
     RefPtrWillBeRawPtr<CSSImageSetValue> value = CSSImageSetValue::create();
     for (auto& item : *this)
         item->isImageValue() ? value->append(toCSSImageValue(*item).valueWithURLMadeAbsolute()) : value->append(item);
     return value.release();
 }
 
 
 } // namespace blink