[css-ui] Add support for caret-color property

third_party/WebKit/Source/core/css/StyleAutoColor.h

+// Copyright 2016 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 StyleAutoColor_h
+#define StyleAutoColor_h
+
+#include "core/css/StyleColor.h"
+
+namespace blink {
+
+class StyleAutoColor : public StyleColor {

[Timothy Loh, 2016/11/28 03:11:21]

This is a weird use of inheritance because it breaks some invariants of the
StyleColor class. Also, shadowing functions as your resolve() does is generally
not a good idea. I would prefer if this class didn't inherit and just stored a
Color and two bools.

[Manuel Rego, 2016/11/28 10:47:55]

Ok, yeah I had doubts about what to do. I'll create a new class for this.

+  DISALLOW_NEW();
+
+ public:
+  StyleAutoColor() : m_autoColor(true) { setCurrentColor(false); }
+  StyleAutoColor(Color color) : StyleColor(color), m_autoColor(false) {}
+  static StyleAutoColor autoColor() { return StyleAutoColor(); }
+  static StyleAutoColor currentColor() {
+    StyleAutoColor currentColor;
+    currentColor.m_autoColor = false;
+    currentColor.setCurrentColor(true);
+    return currentColor;
+  }
+
+  bool isAutoColor() const { return m_autoColor; }
+  Color getColor() const {
+    DCHECK(!isAutoColor());
+    DCHECK(!isCurrentColor());
+    return color();
+  }
+
+  Color resolve(Color currentColor) const {
+    return isAutoColor() || isCurrentColor() ? currentColor : color();
+  }
+
+ private:
+  bool m_autoColor;
+};
+
+inline bool operator==(const StyleAutoColor& a, const StyleAutoColor& b) {
+  if (a.isAutoColor() || b.isAutoColor())
+    return a.isAutoColor() && b.isAutoColor();
+  if (a.isCurrentColor() || b.isCurrentColor())
+    return a.isCurrentColor() && b.isCurrentColor();
+  return a.getColor() == b.getColor();
+}
+
+inline bool operator!=(const StyleAutoColor& a, const StyleAutoColor& b) {
+  return !(a == b);
+}
+
+}  // namespace blink
+
+#endif  // StyleAutoColor_h