[vr] Use base's time classes

chrome/browser/android/vr_shell/animation.cc

 // Copyright 2016 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.
 
 #include "chrome/browser/android/vr_shell/animation.h"
 
 #include <utility>
 
 #include "chrome/browser/android/vr_shell/easing.h"
 
 namespace vr_shell {
 
 Animation::Animation(int id,
                      Property property,
                      std::unique_ptr<easing::Easing> easing,
                      std::vector<float> from,
                      std::vector<float> to,
-                     int64_t start,
-                     int64_t duration)
+                     const base::TimeTicks& start,
+                     const base::TimeDelta& duration)
     : id(id),
       property(property),
       easing(std::move(easing)),
       from(from),
       to(to),
       start(start),
       duration(duration) {}
 
 Animation::~Animation() {}
 
 }  // namespace vr_shell