Improve CSS Style matching spec compliance

Source/core/css/FontStyleMatcher.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 FontStyleMatcher_h
+#define FontStyleMatcher_h
+
+#include "platform/fonts/FontTraits.h"
+
+namespace blink {
+
+class CSSSegmentedFontFace;
+
+class FontStyleMatcher final {
+public:
+    explicit FontStyleMatcher(const FontTraits& fontTraits) : m_fontTraits(fontTraits) {};
+    bool isCandidateBetter(CSSSegmentedFontFace* candidate, CSSSegmentedFontFace* current);
+
+private:
+    FontStyleMatcher();
+    const FontTraits& m_fontTraits;
+};
+
+}
+
+#endif