Add 'base::Time::Max()' to explicitly refer to the end of time.

base/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 time, internally represented as
 // microseconds (s/1,000,000) since a platform-dependent epoch.  Each
 // platform's epoch, along with other system-dependent clock interface
 // routines, is defined in time_PLATFORM.cc.
 //
 // TimeDelta represents a duration of time, internally represented in
@@ skipping 236 matching lines @@
   }
 
   // Returns the time for epoch in Unix-like system (Jan 1, 1970).
   static Time UnixEpoch();
 
   // Returns the current time. Watch out, the system might adjust its clock
   // in which case time will actually go backwards. We don't guarantee that
   // times are increasing, or that two calls to Now() won't be the same.
   static Time Now();
 
+  // Returns the maximum time, which should be greater than any reasonable time
+  // with which we might compare it.
+  static Time Max();
+
   // Returns the current time. Same as Now() except that this function always
   // uses system time so that there are no discrepancies between the returned
   // time and system time even on virtual environments including our test bot.
   // For timing sensitive unittests, this function should be used.
   static Time NowFromSystemTime();
 
   // Converts to/from time_t in UTC and a Time class.
   // TODO(brettw) this should be removed once everybody starts using the |Time|
   // class.
   static Time FromTimeT(time_t tt);
@@ skipping 337 matching lines @@
 #endif
 };
 
 inline TimeTicks TimeDelta::operator+(TimeTicks t) const {
   return TimeTicks(t.ticks_ + delta_);
 }
 
 }  // namespace base
 
 #endif  // BASE_TIME_H_