Add WebPointerProperties type.

public/platform/WebPointerProperties.h

+// Copyright (c) 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 WebPointerProperties_h
+#define WebPointerProperties_h
+
+namespace blink {
+
+// This class encapsulates the properties that are common between mouse and
+// pointer events and touch points as we transition towards the unified pointer
+// event model.
+// TODO(e_hakkinen): Replace WebTouchEvent with WebPointerEvent, remove
+// WebTouchEvent and WebTouchPoint and merge this into WebPointerEvent.
+class WebPointerProperties {
+public:
+    WebPointerProperties()
+        : button(ButtonNone)
+        , id(0)
+        , force(0.f)
+    {
+    }
+
+    enum Button {
+        ButtonNone = -1,
+        ButtonLeft,
+        ButtonMiddle,
+        ButtonRight
+    };
+
+    Button button;
+
+    int id;
+    float force;
+};
+
+} // namespace blink
+
+#endif