class TimeConstants {public:static constexpr int64_t kHoursPerDay = 24;static constexpr int64_t kMillisecondsPerSecond = 1000;static constexpr int64_t kMillisecondsPerDay =kMillisecondsPerSecond * 60 * 60 * kHoursPerDay;// ...
};

class V8_BASE_EXPORT TimeDelta final {public:constexpr TimeDelta() : delta_(0) {}// Converts units of time to TimeDeltas.static constexpr TimeDelta FromDays(int days) {return TimeDelta(days * TimeConstants::kMicrosecondsPerDay);}// ...
}

template <class TimeClass>
class TimeBase : public TimeConstants {public:// ...
int64_t ToInternalValue() const { return us_; }// ...static TimeClass FromInternalValue(int64_t us) { return TimeClass(us); }protected:explicit constexpr TimeBase(int64_t us) : us_(us) {}// Time value in a microsecond timebase.
  int64_t us_;
};

// -----------------------------------------------------------------------------
// Time
//
// This class represents an absolute point in time, internally represented as
// microseconds (s/1,000,000) since 00:00:00 UTC, January 1, 1970.class V8_BASE_EXPORT Time final : public time_internal::TimeBase<Time> {// ...
};

// -----------------------------------------------------------------------------
// TimeTicks
//
// This class represents an abstract time that is most of the time incrementing
// for use in measuring time durations. It is internally represented in
// microseconds.  It can not be converted to a human-readable time, but is
// guaranteed not to decrease (if the user changes the computer clock,
// Time::Now() may actually decrease or jump).  But note that TimeTicks may
// "stand still", for example if the computer suspended.class V8_BASE_EXPORT TimeTicks final : public time_internal::TimeBase<TimeTicks> {// ...
};