Change to calculate the real NTP in TimeTicks.

base/time/time.cc

 // 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.
 
 #include "base/time/time.h"
 
 #include <limits>
 #include <ostream>
 
 #include "base/float_util.h"
+#include "base/lazy_instance.h"
 #include "base/logging.h"
 #include "base/third_party/nspr/prtime.h"
 #include "base/third_party/nspr/prtypes.h"
 
 namespace base {
 
 // TimeDelta ------------------------------------------------------------------
 
 int TimeDelta::InDays() const {
   return static_cast<int>(delta_ / Time::kMicrosecondsPerDay);
@@ skipping 161 matching lines @@
                                        is_local ? PR_FALSE : PR_TRUE,
                                        &result_time);
   if (PR_SUCCESS != result)
     return false;
 
   result_time += kTimeTToMicrosecondsOffset;
   *parsed_time = Time(result_time);
   return true;
 }
 
+// Local helper class to hold the conversion from Time to TickTime at the
+// time of the Unix epoch.
+class UnixEpochSingleton {
+ public:
+  UnixEpochSingleton()
+      : unix_epoch_(TimeTicks::Now() - (Time::Now() - Time::UnixEpoch())) {}
+
+  TimeTicks unix_epoch() const { return unix_epoch_; }
+
+ private:
+  const TimeTicks unix_epoch_;
+
+  DISALLOW_COPY_AND_ASSIGN(UnixEpochSingleton);
+};
+
+static LazyInstance<UnixEpochSingleton>::Leaky
+    leaky_unix_epoch_singleton_instance = LAZY_INSTANCE_INITIALIZER;
+
+// Static
+TimeTicks TimeTicks::UnixEpoch() {
+  return leaky_unix_epoch_singleton_instance.Get().unix_epoch();
+}
+
 // Time::Exploded -------------------------------------------------------------
 
 inline bool is_in_range(int value, int lo, int hi) {
   return lo <= value && value <= hi;
 }
 
 bool Time::Exploded::HasValidValues() const {
   return is_in_range(month, 1, 12) &&
          is_in_range(day_of_week, 0, 6) &&
          is_in_range(day_of_month, 1, 31) &&
          is_in_range(hour, 0, 23) &&
          is_in_range(minute, 0, 59) &&
          is_in_range(second, 0, 60) &&
          is_in_range(millisecond, 0, 999);
 }
 
 }  // namespace base