Implement the new text-size-adjust CSS property

third_party/WebKit/Source/core/style/TextSizeAdjust.h

Index: third_party/WebKit/Source/core/style/TextSizeAdjust.h
diff --git a/third_party/WebKit/Source/core/style/TextSizeAdjust.h b/third_party/WebKit/Source/core/style/TextSizeAdjust.h
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+++ b/third_party/WebKit/Source/core/style/TextSizeAdjust.h
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+// 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 TextSizeAdjust_h
+#define TextSizeAdjust_h
+
+#include "wtf/Allocator.h"
+
+namespace blink {
+
+// Value for text-size-adjust, see: https://drafts.csswg.org/css-size-adjust
+class TextSizeAdjust {
+    DISALLOW_NEW();
+public:
+    TextSizeAdjust(float adjustment) : m_adjustment(adjustment) {}
+
+    // Negative values are invalid so we use them internally to signify 'auto'.
+    static TextSizeAdjust adjustAuto() { return TextSizeAdjust(-1); }
+    // An adjustment of 'none' is equivalent to 100%.
+    static TextSizeAdjust adjustNone() { return TextSizeAdjust(1); }
+
+    bool isAuto() const { return m_adjustment < 0.f; }
+
+    float multiplier() const
+    {
+        // If the adjustment is 'auto', no multiplier is available.
+        DCHECK(!isAuto());
+        return m_adjustment;
+    }
+
+    bool operator==(const TextSizeAdjust& o) const
+    {
+        return m_adjustment == o.m_adjustment;
+    }
+
+    bool operator!=(const TextSizeAdjust& o) const
+    {
+        return !(*this == o);
+    }
+
+private:
+    // Percent adjustment, without units (i.e., 10% is .1 and not 10). Negative
+    // values indicate 'auto' adjustment.
+    float m_adjustment;
+};
+
+} // namespace blink
+
+#endif // TextSizeAdjust_h