Implement a simple checkbox in Sky’s fn2 components library

sky/engine/core/painting/RRect.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 SKY_ENGINE_CORE_PAINTING_RRECT_H_
+#define SKY_ENGINE_CORE_PAINTING_RRECT_H_
+
+#include "sky/engine/core/painting/Rect.h"
+#include "sky/engine/tonic/dart_wrappable.h"
+#include "sky/engine/wtf/PassRefPtr.h"
+#include "sky/engine/wtf/RefCounted.h"
+#include "third_party/skia/include/core/SkRRect.h"
+
+namespace blink {
+
+class RRect : public RefCounted<RRect>, public DartWrappable {
+    DEFINE_WRAPPERTYPEINFO();
+public:
+    ~RRect() override;
+    static PassRefPtr<RRect> create()
+    {
+        return adoptRef(new RRect);
+    }
+
+    void setRectXY(const Rect& rect, float xRad, float yRad);
+
+    const SkRRect& rrect() const { return m_rrect; }
+    void setRRect(const SkRRect& rrect) { m_rrect = rrect; }
+
+private:
+    RRect();
+
+    SkRRect m_rrect;
+};
+
+} // namespace blink
+
+#endif  // SKY_ENGINE_CORE_PAINTING_RRECT_H_