Move base to DEPS

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). System-dependent clock interface routines are
-// defined in time_PLATFORM.cc. Note that values for Time may skew and jump
-// around as the operating system makes adjustments to synchronize (e.g., with
-// NTP servers). Thus, client code that uses the Time class must account for
-// this.
-//
-// TimeDelta represents a duration of time, internally represented in
-// microseconds.
-//
-// TimeTicks, ThreadTicks, and TraceTicks represent an abstract time that is
-// most of the time incrementing, for use in measuring time durations.
-// Internally, they are represented in microseconds. They can not be converted
-// to a human-readable time, but are guaranteed not to decrease (unlike the Time
-// class). Note that TimeTicks may "stand still" (e.g., if the computer is
-// suspended), and ThreadTicks will "stand still" whenever the thread has been
-// de-scheduled by the operating system.
-//
-// All time classes are copyable, assignable, and occupy 64-bits per
-// instance. Thus, they can be efficiently passed by-value (as opposed to
-// by-reference).
-//
-// Definitions of operator<< are provided to make these types work with
-// DCHECK_EQ() and other log macros. For human-readable formatting, see
-// "base/i18n/time_formatting.h".
-//
-// So many choices!  Which time class should you use?  Examples:
-//
-//   Time:        Interpreting the wall-clock time provided by a remote
-//                system. Detecting whether cached resources have
-//                expired. Providing the user with a display of the current date
-//                and time. Determining the amount of time between events across
-//                re-boots of the machine.
-//
-//   TimeTicks:   Tracking the amount of time a task runs. Executing delayed
-//                tasks at the right time. Computing presentation timestamps.
-//                Synchronizing audio and video using TimeTicks as a common
-//                reference clock (lip-sync). Measuring network round-trip
-//                latency.
-//
-//   ThreadTicks: Benchmarking how long the current thread has been doing actual
-//                work.
-//
-//   TraceTicks:  This is only meant to be used by the event tracing
-//                infrastructure, and by outside code modules in special
-//                circumstances.  Please be sure to consult a
-//                base/trace_event/OWNER before committing any new code that
-//                uses this.
-
-#ifndef BASE_TIME_TIME_H_
-#define BASE_TIME_TIME_H_
-
-#include <time.h>
-
-#include <iosfwd>
-
-#include "base/base_export.h"
-#include "base/basictypes.h"
-#include "base/numerics/safe_math.h"
-#include "build/build_config.h"
-
-#if defined(OS_MACOSX)
-#include <CoreFoundation/CoreFoundation.h>
-// Avoid Mac system header macro leak.
-#undef TYPE_BOOL
-#endif
-
-#if defined(OS_POSIX)
-#include <unistd.h>
-#include <sys/time.h>
-#endif
-
-#if defined(OS_WIN)
-// For FILETIME in FromFileTime, until it moves to a new converter class.
-// See TODO(iyengar) below.
-#include <windows.h>
-#endif
-
-#include <limits>
-
-namespace base {
-
-class TimeDelta;
-
-// The functions in the time_internal namespace are meant to be used only by the
-// time classes and functions.  Please use the math operators defined in the
-// time classes instead.
-namespace time_internal {
-
-// Add or subtract |value| from a TimeDelta. The int64 argument and return value
-// are in terms of a microsecond timebase.
-BASE_EXPORT int64 SaturatedAdd(TimeDelta delta, int64 value);
-BASE_EXPORT int64 SaturatedSub(TimeDelta delta, int64 value);
-
-// Clamp |value| on overflow and underflow conditions. The int64 argument and
-// return value are in terms of a microsecond timebase.
-BASE_EXPORT int64 FromCheckedNumeric(const CheckedNumeric<int64> value);
-
-}  // namespace time_internal
-
-// TimeDelta ------------------------------------------------------------------
-
-class BASE_EXPORT TimeDelta {
- public:
-  TimeDelta() : delta_(0) {
-  }
-
-  // Converts units of time to TimeDeltas.
-  static TimeDelta FromDays(int days);
-  static TimeDelta FromHours(int hours);
-  static TimeDelta FromMinutes(int minutes);
-  static TimeDelta FromSeconds(int64 secs);
-  static TimeDelta FromMilliseconds(int64 ms);
-  static TimeDelta FromSecondsD(double secs);
-  static TimeDelta FromMillisecondsD(double ms);
-  static TimeDelta FromMicroseconds(int64 us);
-#if defined(OS_WIN)
-  static TimeDelta FromQPCValue(LONGLONG qpc_value);
-#endif
-
-  // Converts an integer value representing TimeDelta to a class. This is used
-  // when deserializing a |TimeDelta| 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 TimeDelta FromInternalValue(int64 delta) {
-    return TimeDelta(delta);
-  }
-
-  // Returns the maximum time delta, which should be greater than any reasonable
-  // time delta we might compare it to. Adding or subtracting the maximum time
-  // delta to a time or another time delta has an undefined result.
-  static TimeDelta Max();
-
-  // Returns the internal numeric value of the TimeDelta object. Please don't
-  // use this and do arithmetic on it, as it is more error prone than using the
-  // provided operators.
-  // For serializing, use FromInternalValue to reconstitute.
-  int64 ToInternalValue() const {
-    return delta_;
-  }
-
-  // Returns the magnitude (absolute value) of this TimeDelta.
-  TimeDelta magnitude() const {
-    // Some toolchains provide an incomplete C++11 implementation and lack an
-    // int64 overload for std::abs().  The following is a simple branchless
-    // implementation:
-    const int64 mask = delta_ >> (sizeof(delta_) * 8 - 1);
-    return TimeDelta((delta_ + mask) ^ mask);
-  }
-
-  // Returns true if the time delta is zero.
-  bool is_zero() const {
-    return delta_ == 0;
-  }
-
-  // Returns true if the time delta is the maximum time delta.
-  bool is_max() const {
-    return delta_ == std::numeric_limits<int64>::max();
-  }
-
-#if defined(OS_POSIX)
-  struct timespec ToTimeSpec() const;
-#endif
-
-  // Returns the time delta in some unit. The F versions return a floating
-  // point value, the "regular" versions return a rounded-down value.
-  //
-  // InMillisecondsRoundedUp() instead returns an integer that is rounded up
-  // to the next full millisecond.
-  int InDays() const;
-  int InHours() const;
-  int InMinutes() const;
-  double InSecondsF() const;
-  int64 InSeconds() const;
-  double InMillisecondsF() const;
-  int64 InMilliseconds() const;
-  int64 InMillisecondsRoundedUp() const;
-  int64 InMicroseconds() const;
-
-  TimeDelta& operator=(TimeDelta other) {
-    delta_ = other.delta_;
-    return *this;
-  }
-
-  // Computations with other deltas.
-  TimeDelta operator+(TimeDelta other) const {
-    return TimeDelta(time_internal::SaturatedAdd(*this, other.delta_));
-  }
-  TimeDelta operator-(TimeDelta other) const {
-    return TimeDelta(time_internal::SaturatedSub(*this, other.delta_));
-  }
-
-  TimeDelta& operator+=(TimeDelta other) {
-    return *this = (*this + other);
-  }
-  TimeDelta& operator-=(TimeDelta other) {
-    return *this = (*this - other);
-  }
-  TimeDelta operator-() const {
-    return TimeDelta(-delta_);
-  }
-
-  // Computations with numeric types.
-  template<typename T>
-  TimeDelta operator*(T a) const {
-    CheckedNumeric<int64> rv(delta_);
-    rv *= a;
-    return TimeDelta(time_internal::FromCheckedNumeric(rv));
-  }
-  template<typename T>
-  TimeDelta operator/(T a) const {
-    CheckedNumeric<int64> rv(delta_);
-    rv /= a;
-    return TimeDelta(time_internal::FromCheckedNumeric(rv));
-  }
-  template<typename T>
-  TimeDelta& operator*=(T a) {
-    return *this = (*this * a);
-  }
-  template<typename T>
-  TimeDelta& operator/=(T a) {
-    return *this = (*this / a);
-  }
-
-  int64 operator/(TimeDelta a) const {
-    return delta_ / a.delta_;
-  }
-  TimeDelta operator%(TimeDelta a) const {
-    return TimeDelta(delta_ % a.delta_);
-  }
-
-  // Comparison operators.
-  bool operator==(TimeDelta other) const {
-    return delta_ == other.delta_;
-  }
-  bool operator!=(TimeDelta other) const {
-    return delta_ != other.delta_;
-  }
-  bool operator<(TimeDelta other) const {
-    return delta_ < other.delta_;
-  }
-  bool operator<=(TimeDelta other) const {
-    return delta_ <= other.delta_;
-  }
-  bool operator>(TimeDelta other) const {
-    return delta_ > other.delta_;
-  }
-  bool operator>=(TimeDelta other) const {
-    return delta_ >= other.delta_;
-  }
-
- private:
-  friend int64 time_internal::SaturatedAdd(TimeDelta delta, int64 value);
-  friend int64 time_internal::SaturatedSub(TimeDelta delta, int64 value);
-
-  // Constructs a delta given the duration in microseconds. This is private
-  // to avoid confusion by callers with an integer constructor. Use
-  // FromSeconds, FromMilliseconds, etc. instead.
-  explicit TimeDelta(int64 delta_us) : delta_(delta_us) {
-  }
-
-  // Delta in microseconds.
-  int64 delta_;
-};
-
-template<typename T>
-inline TimeDelta operator*(T a, TimeDelta td) {
-  return td * a;
-}
-
-// For logging use only.
-BASE_EXPORT std::ostream& operator<<(std::ostream& os, TimeDelta time_delta);
-
-// Do not reference the time_internal::TimeBase template class directly.  Please
-// use one of the time subclasses instead, and only reference the public
-// TimeBase members via those classes.
-namespace time_internal {
-
-// TimeBase--------------------------------------------------------------------
-
-// Provides value storage and comparison/math operations common to all time
-// classes. Each subclass provides for strong type-checking to ensure
-// semantically meaningful comparison/math of time values from the same clock
-// source or timeline.
-template<class TimeClass>
-class TimeBase {
- 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 * kHoursPerDay;
-  static const int64 kMicrosecondsPerWeek = kMicrosecondsPerDay * 7;
-  static const int64 kNanosecondsPerMicrosecond = 1000;
-  static const int64 kNanosecondsPerSecond = kNanosecondsPerMicrosecond *
-                                             kMicrosecondsPerSecond;
-
-  // Returns true if this object has not been initialized.
-  //
-  // Warning: Be careful when writing code that performs math on time values,
-  // since it's possible to produce a valid "zero" result that should not be
-  // interpreted as a "null" value.
-  bool is_null() const {
-    return us_ == 0;
-  }
-
-  // Returns true if this object represents the maximum time.
-  bool is_max() const {
-    return us_ == std::numeric_limits<int64>::max();
-  }
-
-  // For serializing only. Use FromInternalValue() to reconstitute. Please don't
-  // use this and do arithmetic on it, as it is more error prone than using the
-  // provided operators.
-  int64 ToInternalValue() const {
-    return us_;
-  }
-
-  TimeClass& operator=(TimeClass other) {
-    us_ = other.us_;
-    return *(static_cast<TimeClass*>(this));
-  }
-
-  // Compute the difference between two times.
-  TimeDelta operator-(TimeClass other) const {
-    return TimeDelta::FromMicroseconds(us_ - other.us_);
-  }
-
-  // Return a new time modified by some delta.
-  TimeClass operator+(TimeDelta delta) const {
-    return TimeClass(time_internal::SaturatedAdd(delta, us_));
-  }
-  TimeClass operator-(TimeDelta delta) const {
-    return TimeClass(-time_internal::SaturatedSub(delta, us_));
-  }
-
-  // Modify by some time delta.
-  TimeClass& operator+=(TimeDelta delta) {
-    return static_cast<TimeClass&>(*this = (*this + delta));
-  }
-  TimeClass& operator-=(TimeDelta delta) {
-    return static_cast<TimeClass&>(*this = (*this - delta));
-  }
-
-  // Comparison operators
-  bool operator==(TimeClass other) const {
-    return us_ == other.us_;
-  }
-  bool operator!=(TimeClass other) const {
-    return us_ != other.us_;
-  }
-  bool operator<(TimeClass other) const {
-    return us_ < other.us_;
-  }
-  bool operator<=(TimeClass other) const {
-    return us_ <= other.us_;
-  }
-  bool operator>(TimeClass other) const {
-    return us_ > other.us_;
-  }
-  bool operator>=(TimeClass other) const {
-    return us_ >= other.us_;
-  }
-
-  // Converts an integer value representing TimeClass to a class. This is used
-  // when deserializing a |TimeClass| 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 TimeClass FromInternalValue(int64 us) {
-    return TimeClass(us);
-  }
-
- protected:
-  explicit TimeBase(int64 us) : us_(us) {
-  }
-
-  // Time value in a microsecond timebase.
-  int64 us_;
-};
-
-}  // namespace time_internal
-
-template<class TimeClass>
-inline TimeClass operator+(TimeDelta delta, TimeClass t) {
-  return t + delta;
-}
-
-// Time -----------------------------------------------------------------------
-
-// Represents a wall clock time in UTC. Values are not guaranteed to be
-// monotonically non-decreasing and are subject to large amounts of skew.
-class BASE_EXPORT Time : public time_internal::TimeBase<Time> {
- public:
-  // The representation of Jan 1, 1970 UTC in microseconds since the
-  // platform-dependent epoch.
-  static const int64 kTimeTToMicrosecondsOffset;
-
-#if !defined(OS_WIN)
-  // On Mac & Linux, this value is the delta from the Windows epoch of 1601 to
-  // the Posix delta of 1970. This is used for migrating between the old
-  // 1970-based epochs to the new 1601-based ones. It should be removed from
-  // this global header and put in the platform-specific ones when we remove the
-  // migration code.
-  static const int64 kWindowsEpochDeltaMicroseconds;
-#else
-  // To avoid overflow in QPC to Microseconds calculations, since we multiply
-  // by kMicrosecondsPerSecond, then the QPC value should not exceed
-  // (2^63 - 1) / 1E6. If it exceeds that threshold, we divide then multiply.
-  static const int64 kQPCOverflowThreshold = 0x8637BD05AF7;
-#endif
-
-  // Represents an exploded time that can be formatted nicely. This is kind of
-  // like the Win32 SYSTEMTIME structure or the Unix "struct tm" with a few
-  // additions and changes to prevent errors.
-  struct BASE_EXPORT Exploded {
-    int year;          // Four digit year "2007"
-    int month;         // 1-based month (values 1 = January, etc.)
-    int day_of_week;   // 0-based day of week (0 = Sunday, etc.)
-    int day_of_month;  // 1-based day of month (1-31)
-    int hour;          // Hour within the current day (0-23)
-    int minute;        // Minute within the current hour (0-59)
-    int second;        // Second within the current minute (0-59 plus leap
-                       //   seconds which may take it up to 60).
-    int millisecond;   // Milliseconds within the current second (0-999)
-
-    // A cursory test for whether the data members are within their
-    // respective ranges. A 'true' return value does not guarantee the
-    // Exploded value can be successfully converted to a Time value.
-    bool HasValidValues() const;
-  };
-
-  // Contains the NULL time. Use Time::Now() to get the current time.
-  Time() : TimeBase(0) {
-  }
-
-  // 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);
-  time_t ToTimeT() const;
-
-  // Converts time to/from a double which is the number of seconds since epoch
-  // (Jan 1, 1970).  Webkit uses this format to represent time.
-  // Because WebKit initializes double time value to 0 to indicate "not
-  // initialized", we map it to empty Time object that also means "not
-  // initialized".
-  static Time FromDoubleT(double dt);
-  double ToDoubleT() const;
-
-#if defined(OS_POSIX)
-  // Converts the timespec structure to time. MacOS X 10.8.3 (and tentatively,
-  // earlier versions) will have the |ts|'s tv_nsec component zeroed out,
-  // having a 1 second resolution, which agrees with
-  // https://developer.apple.com/legacy/library/#technotes/tn/tn1150.html#HFSPlusDates.
-  static Time FromTimeSpec(const timespec& ts);
-#endif
-
-  // Converts to/from the Javascript convention for times, a number of
-  // milliseconds since the epoch:
-  // https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Date/getTime.
-  static Time FromJsTime(double ms_since_epoch);
-  double ToJsTime() const;
-
-  // Converts to Java convention for times, a number of
-  // milliseconds since the epoch.
-  int64 ToJavaTime() const;
-
-#if defined(OS_POSIX)
-  static Time FromTimeVal(struct timeval t);
-  struct timeval ToTimeVal() const;
-#endif
-
-#if defined(OS_MACOSX)
-  static Time FromCFAbsoluteTime(CFAbsoluteTime t);
-  CFAbsoluteTime ToCFAbsoluteTime() const;
-#endif
-
-#if defined(OS_WIN)
-  static Time FromFileTime(FILETIME ft);
-  FILETIME ToFileTime() const;
-
-  // The minimum time of a low resolution timer.  This is basically a windows
-  // constant of ~15.6ms.  While it does vary on some older OS versions, we'll
-  // treat it as static across all windows versions.
-  static const int kMinLowResolutionThresholdMs = 16;
-
-  // Enable or disable Windows high resolution timer.
-  static void EnableHighResolutionTimer(bool enable);
-
-  // Activates or deactivates the high resolution timer based on the |activate|
-  // flag.  If the HighResolutionTimer is not Enabled (see
-  // EnableHighResolutionTimer), this function will return false.  Otherwise
-  // returns true.  Each successful activate call must be paired with a
-  // subsequent deactivate call.
-  // All callers to activate the high resolution timer must eventually call
-  // this function to deactivate the high resolution timer.
-  static bool ActivateHighResolutionTimer(bool activate);
-
-  // Returns true if the high resolution timer is both enabled and activated.
-  // This is provided for testing only, and is not tracked in a thread-safe
-  // way.
-  static bool IsHighResolutionTimerInUse();
-#endif
-
-  // Converts an exploded structure representing either the local time or UTC
-  // into a Time class.
-  static Time FromUTCExploded(const Exploded& exploded) {
-    return FromExploded(false, exploded);
-  }
-  static Time FromLocalExploded(const Exploded& exploded) {
-    return FromExploded(true, exploded);
-  }
-
-  // Converts a string representation of time to a Time object.
-  // An example of a time string which is converted is as below:-
-  // "Tue, 15 Nov 1994 12:45:26 GMT". If the timezone is not specified
-  // in the input string, FromString assumes local time and FromUTCString
-  // assumes UTC. A timezone that cannot be parsed (e.g. "UTC" which is not
-  // specified in RFC822) is treated as if the timezone is not specified.
-  // TODO(iyengar) Move the FromString/FromTimeT/ToTimeT/FromFileTime to
-  // a new time converter class.
-  static bool FromString(const char* time_string, Time* parsed_time) {
-    return FromStringInternal(time_string, true, parsed_time);
-  }
-  static bool FromUTCString(const char* time_string, Time* parsed_time) {
-    return FromStringInternal(time_string, false, parsed_time);
-  }
-
-  // Fills the given exploded structure with either the local time or UTC from
-  // this time structure (containing UTC).
-  void UTCExplode(Exploded* exploded) const {
-    return Explode(false, exploded);
-  }
-  void LocalExplode(Exploded* exploded) const {
-    return Explode(true, exploded);
-  }
-
-  // Rounds this time down to the nearest day in local time. It will represent
-  // midnight on that day.
-  Time LocalMidnight() const;
-
- private:
-  friend class time_internal::TimeBase<Time>;
-
-  explicit Time(int64 us) : TimeBase(us) {
-  }
-
-  // Explodes the given time to either local time |is_local = true| or UTC
-  // |is_local = false|.
-  void Explode(bool is_local, Exploded* exploded) const;
-
-  // Unexplodes a given time assuming the source is either local time
-  // |is_local = true| or UTC |is_local = false|.
-  static Time FromExploded(bool is_local, const Exploded& exploded);
-
-  // Converts a string representation of time to a Time object.
-  // An example of a time string which is converted is as below:-
-  // "Tue, 15 Nov 1994 12:45:26 GMT". If the timezone is not specified
-  // in the input string, local time |is_local = true| or
-  // UTC |is_local = false| is assumed. A timezone that cannot be parsed
-  // (e.g. "UTC" which is not specified in RFC822) is treated as if the
-  // timezone is not specified.
-  static bool FromStringInternal(const char* time_string,
-                                 bool is_local,
-                                 Time* parsed_time);
-};
-
-// Inline the TimeDelta factory methods, for fast TimeDelta construction.
-
-// static
-inline TimeDelta TimeDelta::FromDays(int days) {
-  // Preserve max to prevent overflow.
-  if (days == std::numeric_limits<int>::max())
-    return Max();
-  return TimeDelta(days * Time::kMicrosecondsPerDay);
-}
-
-// static
-inline TimeDelta TimeDelta::FromHours(int hours) {
-  // Preserve max to prevent overflow.
-  if (hours == std::numeric_limits<int>::max())
-    return Max();
-  return TimeDelta(hours * Time::kMicrosecondsPerHour);
-}
-
-// static
-inline TimeDelta TimeDelta::FromMinutes(int minutes) {
-  // Preserve max to prevent overflow.
-  if (minutes == std::numeric_limits<int>::max())
-    return Max();
-  return TimeDelta(minutes * Time::kMicrosecondsPerMinute);
-}
-
-// static
-inline TimeDelta TimeDelta::FromSeconds(int64 secs) {
-  // Preserve max to prevent overflow.
-  if (secs == std::numeric_limits<int64>::max())
-    return Max();
-  return TimeDelta(secs * Time::kMicrosecondsPerSecond);
-}
-
-// static
-inline TimeDelta TimeDelta::FromMilliseconds(int64 ms) {
-  // Preserve max to prevent overflow.
-  if (ms == std::numeric_limits<int64>::max())
-    return Max();
-  return TimeDelta(ms * Time::kMicrosecondsPerMillisecond);
-}
-
-// static
-inline TimeDelta TimeDelta::FromSecondsD(double secs) {
-  // Preserve max to prevent overflow.
-  if (secs == std::numeric_limits<double>::infinity())
-    return Max();
-  return TimeDelta(static_cast<int64>(secs * Time::kMicrosecondsPerSecond));
-}
-
-// static
-inline TimeDelta TimeDelta::FromMillisecondsD(double ms) {
-  // Preserve max to prevent overflow.
-  if (ms == std::numeric_limits<double>::infinity())
-    return Max();
-  return TimeDelta(static_cast<int64>(ms * Time::kMicrosecondsPerMillisecond));
-}
-
-// static
-inline TimeDelta TimeDelta::FromMicroseconds(int64 us) {
-  // Preserve max to prevent overflow.
-  if (us == std::numeric_limits<int64>::max())
-    return Max();
-  return TimeDelta(us);
-}
-
-// For logging use only.
-BASE_EXPORT std::ostream& operator<<(std::ostream& os, Time time);
-
-// TimeTicks ------------------------------------------------------------------
-
-// Represents monotonically non-decreasing clock time.
-class BASE_EXPORT TimeTicks : public time_internal::TimeBase<TimeTicks> {
- public:
-  TimeTicks() : TimeBase(0) {
-  }
-
-  // Platform-dependent tick count representing "right now." When
-  // IsHighResolution() returns false, the resolution of the clock could be
-  // as coarse as ~15.6ms. Otherwise, the resolution should be no worse than one
-  // microsecond.
-  static TimeTicks Now();
-
-  // Returns true if the high resolution clock is working on this system and
-  // Now() will return high resolution values. Note that, on systems where the
-  // high resolution clock works but is deemed inefficient, the low resolution
-  // clock will be used instead.
-  static bool IsHighResolution();
-
-#if defined(OS_WIN)
-  // Translates an absolute QPC timestamp into a TimeTicks value. The returned
-  // value has the same origin as Now(). Do NOT attempt to use this if
-  // IsHighResolution() returns false.
-  static TimeTicks FromQPCValue(LONGLONG qpc_value);
-#endif
-
-  // 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: 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.
-  static TimeTicks UnixEpoch();
-
-  // Returns |this| snapped to the next tick, given a |tick_phase| and
-  // repeating |tick_interval| in both directions. |this| may be before,
-  // after, or equal to the |tick_phase|.
-  TimeTicks SnappedToNextTick(TimeTicks tick_phase,
-                              TimeDelta tick_interval) const;
-
-#if defined(OS_WIN)
- protected:
-  typedef DWORD (*TickFunctionType)(void);
-  static TickFunctionType SetMockTickFunction(TickFunctionType ticker);
-#endif
-
- private:
-  friend class time_internal::TimeBase<TimeTicks>;
-
-  // Please use Now() to create a new object. This is for internal use
-  // and testing.
-  explicit TimeTicks(int64 us) : TimeBase(us) {
-  }
-};
-
-// For logging use only.
-BASE_EXPORT std::ostream& operator<<(std::ostream& os, TimeTicks time_ticks);
-
-// ThreadTicks ----------------------------------------------------------------
-
-// Represents a clock, specific to a particular thread, than runs only while the
-// thread is running.
-class BASE_EXPORT ThreadTicks : public time_internal::TimeBase<ThreadTicks> {
- public:
-  ThreadTicks() : TimeBase(0) {
-  }
-
-  // Returns true if ThreadTicks::Now() is supported on this system.
-  static bool IsSupported() {
-#if (defined(_POSIX_THREAD_CPUTIME) && (_POSIX_THREAD_CPUTIME >= 0)) || \
-    defined(OS_MACOSX) || defined(OS_ANDROID)
-    return true;
-#else
-    return false;
-#endif
-  }
-
-  // Returns thread-specific CPU-time on systems that support this feature.
-  // Needs to be guarded with a call to IsSupported(). Use this timer
-  // to (approximately) measure how much time the calling thread spent doing
-  // actual work vs. being de-scheduled. May return bogus results if the thread
-  // migrates to another CPU between two calls.
-  static ThreadTicks Now();
-
- private:
-  friend class time_internal::TimeBase<ThreadTicks>;
-
-  // Please use Now() to create a new object. This is for internal use
-  // and testing.
-  explicit ThreadTicks(int64 us) : TimeBase(us) {
-  }
-};
-
-// For logging use only.
-BASE_EXPORT std::ostream& operator<<(std::ostream& os, ThreadTicks time_ticks);
-
-// TraceTicks ----------------------------------------------------------------
-
-// Represents high-resolution system trace clock time.
-class BASE_EXPORT TraceTicks : public time_internal::TimeBase<TraceTicks> {
- public:
-  // We define this even without OS_CHROMEOS for seccomp sandbox testing.
-#if defined(OS_LINUX)
-  // Force definition of the system trace clock; it is a chromeos-only api
-  // at the moment and surfacing it in the right place requires mucking
-  // with glibc et al.
-  static const clockid_t kClockSystemTrace = 11;
-#endif
-
-  TraceTicks() : TimeBase(0) {
-  }
-
-  // Returns the current system trace time or, if not available on this
-  // platform, a high-resolution time value; or a low-resolution time value if
-  // neither are avalable. On systems where a global trace clock is defined,
-  // timestamping TraceEvents's with this value guarantees synchronization
-  // between events collected inside chrome and events collected outside
-  // (e.g. kernel, X server).
-  //
-  // On some platforms, the clock source used for tracing can vary depending on
-  // hardware and/or kernel support.  Do not make any assumptions without
-  // consulting the documentation for this functionality in the time_win.cc,
-  // time_posix.cc, etc. files.
-  //
-  // NOTE: This is only meant to be used by the event tracing infrastructure,
-  // and by outside code modules in special circumstances.  Please be sure to
-  // consult a base/trace_event/OWNER before committing any new code that uses
-  // this.
-  static TraceTicks Now();
-
- private:
-  friend class time_internal::TimeBase<TraceTicks>;
-
-  // Please use Now() to create a new object. This is for internal use
-  // and testing.
-  explicit TraceTicks(int64 us) : TimeBase(us) {
-  }
-};
-
-// For logging use only.
-BASE_EXPORT std::ostream& operator<<(std::ostream& os, TraceTicks time_ticks);
-
-}  // namespace base
-
-#endif  // BASE_TIME_TIME_H_