Improve Material ink effects

sky/engine/core/events/GestureEvent.idl

 // Copyright 2014 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.
 
 [
     EventConstructor,
 ] interface GestureEvent : Event {
+    [InitializedByEventConstructor] readonly attribute long primaryPointer;
     [InitializedByEventConstructor] readonly attribute double x;
     [InitializedByEventConstructor] readonly attribute double y;
     [InitializedByEventConstructor] readonly attribute double dx;
     [InitializedByEventConstructor] readonly attribute double dy;
     [InitializedByEventConstructor] readonly attribute double velocityX;
     [InitializedByEventConstructor] readonly attribute double velocityY;
 };