Add Chromium-style TimeDelta, Time and TimeTicks classes, and a new ElapsedTimer class.

src/platform-posix.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 300 matching lines @@
   struct rusage usage;
 
   if (getrusage(RUSAGE_SELF, &usage) < 0) return -1;
   *secs = usage.ru_utime.tv_sec;
   *usecs = usage.ru_utime.tv_usec;
   return 0;
 }
 
 
 double OS::TimeCurrentMillis() {
-  struct timeval tv;
-  if (gettimeofday(&tv, NULL) < 0) return 0.0;
-  return (static_cast<double>(tv.tv_sec) * 1000) +
-         (static_cast<double>(tv.tv_usec) / 1000);
+  return Time::Now().ToJsTime();
 }
 
 
-int64_t OS::Ticks() {
-  // gettimeofday has microsecond resolution.
-  struct timeval tv;
-  if (gettimeofday(&tv, NULL) < 0)
-    return 0;
-  return (static_cast<int64_t>(tv.tv_sec) * 1000000) + tv.tv_usec;
-}
-
-
 double OS::DaylightSavingsOffset(double time) {
   if (std::isnan(time)) return nan_value();
   time_t tv = static_cast<time_t>(floor(time/msPerSecond));
   struct tm* t = localtime(&tv);
   if (NULL == t) return nan_value();
   return t->tm_isdst > 0 ? 3600 * msPerSecond : 0;
 }
 
 
 int OS::GetLastError() {
@@ skipping 643 matching lines @@
   return ntohl(value);
 }
 
 
 Socket* OS::CreateSocket() {
   return new POSIXSocket();
 }
 
 
 } }  // namespace v8::internal