Update from https://crrev.com/320931

base/time/time.h

 // Copyright (c) 2012 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.
 
 // Time represents an absolute point in coordinated universal time (UTC),
 // internally represented as microseconds (s/1,000,000) since the Windows epoch
 // (1601-01-01 00:00:00 UTC) (See http://crbug.com/14734).  System-dependent
 // clock interface routines are defined in time_PLATFORM.cc.
 //
 // TimeDelta represents a duration of time, internally represented in
@@ skipping 215 matching lines @@
 }
 
 // For logging use only.
 BASE_EXPORT std::ostream& operator<<(std::ostream& os, TimeDelta time_delta);
 
 // Time -----------------------------------------------------------------------
 
 // Represents a wall clock time in UTC.
 class BASE_EXPORT Time {
  public:
+  static const int64 kHoursPerDay = 24;
   static const int64 kMillisecondsPerSecond = 1000;
+  static const int64 kMillisecondsPerDay = kMillisecondsPerSecond * 60 * 60 *
+                                           kHoursPerDay;
   static const int64 kMicrosecondsPerMillisecond = 1000;
   static const int64 kMicrosecondsPerSecond = kMicrosecondsPerMillisecond *
                                               kMillisecondsPerSecond;
   static const int64 kMicrosecondsPerMinute = kMicrosecondsPerSecond * 60;
   static const int64 kMicrosecondsPerHour = kMicrosecondsPerMinute * 60;
-  static const int64 kMicrosecondsPerDay = kMicrosecondsPerHour * 24;
+  static const int64 kMicrosecondsPerDay = kMicrosecondsPerHour * kHoursPerDay;
   static const int64 kMicrosecondsPerWeek = kMicrosecondsPerDay * 7;
   static const int64 kNanosecondsPerMicrosecond = 1000;
   static const int64 kNanosecondsPerSecond = kNanosecondsPerMicrosecond *
                                              kMicrosecondsPerSecond;
 
   // The representation of Jan 1, 1970 UTC in microseconds since the
   // platform-dependent epoch.
   static const int64 kTimeTToMicrosecondsOffset;
 
 #if !defined(OS_WIN)
@@ skipping 505 matching lines @@
 inline TimeTicks TimeDelta::operator+(TimeTicks t) const {
   return TimeTicks(t.ticks_ + delta_);
 }
 
 // For logging use only.
 BASE_EXPORT std::ostream& operator<<(std::ostream& os, TimeTicks time_ticks);
 
 }  // namespace base
 
 #endif  // BASE_TIME_TIME_H_