Don't animate caret-color: auto

third_party/WebKit/Source/core/animation/ColorPropertyFunctions.h

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef ColorPropertyFunctions_h
 #define ColorPropertyFunctions_h
 
 #include "core/CSSPropertyNames.h"
 #include "core/css/StyleColor.h"
 
 namespace blink {
 
 class ComputedStyle;
 
+struct OptionalStyleColor {
+ public:
+  OptionalStyleColor(std::nullptr_t) : m_isNull(true) {}
+  OptionalStyleColor(const StyleColor& styleColor)
+      : m_isNull(false), m_styleColor(styleColor) {}
+  OptionalStyleColor(const Color& color)
+      : m_isNull(false), m_styleColor(color) {}
+
+  bool isNull() const { return m_isNull; }
+  const StyleColor& access() const {
+    DCHECK(!m_isNull);
+    return m_styleColor;
+  }
+  bool operator==(const OptionalStyleColor& other) const {
+    return m_isNull == other.m_isNull && m_styleColor == other.m_styleColor;
+  }
+
+ private:
+  bool m_isNull;
+  StyleColor m_styleColor;
+};
+
 class ColorPropertyFunctions {
  public:
-  static bool getInitialColor(CSSPropertyID, StyleColor& initialColor);
-  static StyleColor getUnvisitedColor(CSSPropertyID, const ComputedStyle&);
-  static StyleColor getVisitedColor(CSSPropertyID, const ComputedStyle&);
+  static OptionalStyleColor getInitialColor(CSSPropertyID);
+  static OptionalStyleColor getUnvisitedColor(CSSPropertyID,
+                                              const ComputedStyle&);
+  static OptionalStyleColor getVisitedColor(CSSPropertyID,
+                                            const ComputedStyle&);
   static void setUnvisitedColor(CSSPropertyID, ComputedStyle&, const Color&);
   static void setVisitedColor(CSSPropertyID, ComputedStyle&, const Color&);
 };
 
 }  // namespace blink
 
 #endif  // ColorPropertyFunctions_h