Change to calculate the real NTP in TimeTicks.

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 time, 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 586 matching lines @@
   }
 
   // Converts an integer value representing TimeTicks to a class. This is used
   // when deserializing a |TimeTicks| structure, using a value known to be
   // compatible. It is not provided as a constructor because the integer type
   // may be unclear from the perspective of a caller.
   static TimeTicks FromInternalValue(int64 ticks) {
     return TimeTicks(ticks);
   }
 
+  // Get the TimeTick value at the time of the UnixEpoch. This is useful when
+  // you need to relate the value of TimeTicks to a real time and date.
+  // Note: this function will return the same value during the duration of
+  // the application; however it might change for next run since your TickClock

[miu, 2013/10/24 21:48:52]

nit: For clarity, I would replace the "Note:" text with something that describes
what's happening underneath in more detail.  Like:

  Note: Upon first invocation, this function takes a snapshot of the realtime
clock to establish a reference point.  This function will return the same value
for the duration of the application, but will be different in future application
runs.

[pwestin, 2013/10/24 22:39:52]

Done.

+  // might have a different starting point.
+  static TimeTicks UnixEpoch();
+
   // Returns the internal numeric value of the TimeTicks object.
   // For serializing, use FromInternalValue to reconstitute.
   int64 ToInternalValue() const {
     return ticks_;
   }
 
   TimeTicks& operator=(TimeTicks other) {
     ticks_ = other.ticks_;
     return *this;
   }
@@ skipping 58 matching lines @@
 #endif
 };
 
 inline TimeTicks TimeDelta::operator+(TimeTicks t) const {
   return TimeTicks(t.ticks_ + delta_);
 }
 
 }  // namespace base
 
 #endif  // BASE_TIME_TIME_H_