Touch.identifier should be long, not unsigned long

Source/core/dom/Touch.idl

 /*
  * Copyright 2008, The Android Open Source Project
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *  * Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  *  * Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 10 matching lines @@
  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 // http://rawgit.com/w3c/touch-events/v1-errata/touchevents.html#touch-interface
 
 [
     WillBeGarbageCollected,
 ] interface Touch {
-    // FIXME: identifier should be long, not unsigned long.
-    readonly attribute unsigned long identifier;
+    readonly attribute long identifier;
     readonly attribute EventTarget target;
     readonly attribute double screenX;
     readonly attribute double screenY;
     readonly attribute double clientX;
     readonly attribute double clientY;
     readonly attribute double pageX;
     readonly attribute double pageY;
 
     // Touch Events Extensions
     // http://rawgit.com/w3c/touch-events/master/touchevents.html#touch-interface
     readonly attribute float radiusX;
     readonly attribute float radiusY;
     readonly attribute float rotationAngle;
     readonly attribute float force;
 
     // Non-standard APIs
     [DeprecateAs=PrefixedTouchRadiusX, ImplementedAs=radiusX] readonly attribute float webkitRadiusX;
     [DeprecateAs=PrefixedTouchRadiusY, ImplementedAs=radiusY] readonly attribute float webkitRadiusY;
     [DeprecateAs=PrefixedTouchRotationAngle, ImplementedAs=rotationAngle] readonly attribute float webkitRotationAngle;
     [DeprecateAs=PrefixedTouchForce, ImplementedAs=force] readonly attribute float webkitForce;
 };