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

third_party/WebKit/Source/core/paint/PaintLayerStackingNode.cpp

 /*
  * Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011, 2012 Apple Inc. All rights reserved.
  *
  * Portions are Copyright (C) 1998 Netscape Communications Corporation.
  *
  * Other contributors:
  *   Robert O'Callahan <roc+@cs.cmu.edu>
  *   David Baron <dbaron@fas.harvard.edu>
  *   Christian Biesinger <cbiesinger@web.de>
  *   Randall Jesup <rjesup@wgate.com>
@@ skipping 30 matching lines @@
  * version of this file under any of the LGPL, the MPL or the GPL.
  */
 
 #include "config.h"
 #include "core/paint/PaintLayerStackingNode.h"
 
 #include "core/layout/LayoutView.h"
 #include "core/layout/compositing/PaintLayerCompositor.h"
 #include "core/paint/PaintLayer.h"
 #include "public/platform/Platform.h"
+#include <algorithm>
 
 namespace blink {
 
 // FIXME: This should not require PaintLayer. There is currently a cycle where
 // in order to determine if we shoulBeTreatedAsStackingContext() we have to ask the paint
 // layer about some of its state.
 PaintLayerStackingNode::PaintLayerStackingNode(PaintLayer* layer)
     : m_layer(layer)
 #if ENABLE(ASSERT)
     , m_layerListMutationAllowed(true)
@@ skipping 194 matching lines @@
     }
     return 0;
 }
 
 LayoutBoxModelObject* PaintLayerStackingNode::layoutObject() const
 {
     return m_layer->layoutObject();
 }
 
 } // namespace blink