Deprecate step timing with position 'middle'

third_party/WebKit/Source/core/css/resolver/CSSToStyleMap.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) 2012 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 14 matching lines @@
 
 #include "core/CSSPropertyNames.h"
 #include "core/animation/Timing.h"
 #include "core/animation/css/CSSTransitionData.h"
 #include "core/style/ComputedStyleConstants.h"
 #include "platform/animation/TimingFunction.h"
 #include "platform/wtf/Allocator.h"
 
 namespace blink {
 
+class Document;
 class FillLayer;
 class CSSValue;
 class StyleResolverState;
 class NinePieceImage;
 class BorderImageLengthBox;
 
 class CSSToStyleMap {
   STATIC_ONLY(CSSToStyleMap);
 
  public:
@@ skipping 24 matching lines @@
 
   static double MapAnimationDelay(const CSSValue&);
   static Timing::PlaybackDirection MapAnimationDirection(const CSSValue&);
   static double MapAnimationDuration(const CSSValue&);
   static Timing::FillMode MapAnimationFillMode(const CSSValue&);
   static double MapAnimationIterationCount(const CSSValue&);
   static AtomicString MapAnimationName(const CSSValue&);
   static EAnimPlayState MapAnimationPlayState(const CSSValue&);
   static CSSTransitionData::TransitionProperty MapAnimationProperty(
       const CSSValue&);
+
+  // Pass a Document* if allow_step_middle is true so that the usage can be
+  // counted.
   static PassRefPtr<TimingFunction> MapAnimationTimingFunction(
       const CSSValue&,
-      bool allow_step_middle = false);
+      bool allow_step_middle = false,
+      Document* = nullptr);
 
   static void MapNinePieceImage(StyleResolverState&,
                                 CSSPropertyID,
                                 const CSSValue&,
                                 NinePieceImage&);
   static void MapNinePieceImageSlice(StyleResolverState&,
                                      const CSSValue&,
                                      NinePieceImage&);
   static BorderImageLengthBox MapNinePieceImageQuad(StyleResolverState&,
                                                     const CSSValue&);
   static void MapNinePieceImageRepeat(StyleResolverState&,
                                       const CSSValue&,
                                       NinePieceImage&);
 };
 
 }  // namespace blink
 
 #endif