Add wheel support to sky-scrollable

sky/engine/core/events/WheelEvent.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_EVENTS_WHEELEVENT_H_
+#define SKY_ENGINE_CORE_EVENTS_WHEELEVENT_H_
+
+#include "sky/engine/core/events/Event.h"
+#include "sky/engine/public/platform/WebInputEvent.h"
+
+namespace blink {
+
+struct WheelEventInit : public EventInit {
+    double x = 0;
+    double y = 0;
+    double offsetX = 0;
+    double offsetY = 0;
+};
+
+class WheelEvent : public Event {
+    DEFINE_WRAPPERTYPEINFO();
+public:
+    static PassRefPtr<WheelEvent> create()
+    {
+        return adoptRef(new WheelEvent);
+    }
+    static PassRefPtr<WheelEvent> create(const WebWheelEvent& event)
+    {
+        return adoptRef(new WheelEvent(event));
+    }
+    static PassRefPtr<WheelEvent> create(const AtomicString& type, const WheelEventInit& initializer)
+    {
+        return adoptRef(new WheelEvent(type, initializer));
+    }
+
+    ~WheelEvent() override;
+    const AtomicString& interfaceName() const override;
+
+    double x() const { return m_x; }
+    double y() const { return m_y; }
+    double offsetX() const { return m_offsetX; }
+    double offsetY() const { return m_offsetY; }
+
+private:
+    WheelEvent();
+    explicit WheelEvent(const WebWheelEvent& event);
+    WheelEvent(const AtomicString&, const WheelEventInit&);
+
+    double m_x;
+    double m_y;
+    double m_offsetX;
+    double m_offsetY;
+};
+
+} // namespace blink
+
+#endif  // SKY_ENGINE_CORE_EVENTS_WHEELEVENT_H_