Updated VRPose.timestamp to use same casing as WebVR spec.

third_party/WebKit/Source/modules/vr/VRPose.idl

 // 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.
 
 // http://mozvr.github.io/webvr-spec/webvr.html#vrpose
 [
     RuntimeEnabled=WebVR,
 ] interface VRPose {
-    readonly attribute double timeStamp;
+    readonly attribute DOMHighResTimeStamp timestamp;
     readonly attribute Float32Array? position;
     readonly attribute Float32Array? linearVelocity;
     readonly attribute Float32Array? linearAcceleration;
     readonly attribute Float32Array? orientation;
     readonly attribute Float32Array? angularVelocity;
     readonly attribute Float32Array? angularAcceleration;
 };