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

src/platform.h

 // 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 188 matching lines @@
 
   // Clean up platform-OS-related things. Called once at VM shutdown.
   static void TearDown();
 
   // Returns the accumulated user time for thread. This routine
   // can be used for profiling. The implementation should
   // strive for high-precision timer resolution, preferable
   // micro-second resolution.
   static int GetUserTime(uint32_t* secs,  uint32_t* usecs);
 
-  // Get a tick counter normalized to one tick per microsecond.
-  // Used for calculating time intervals.
-  static int64_t Ticks();
-
   // Returns current time as the number of milliseconds since
   // 00:00:00 UTC, January 1, 1970.
   static double TimeCurrentMillis();
 
   // Returns a string identifying the current time zone. The
   // timestamp is used for determining if DST is in effect.
   static const char* LocalTimezone(double time);
 
   // Returns the local time offset in milliseconds east of UTC without
   // taking daylight savings time into account.
@@ skipping 582 matching lines @@
   static uint16_t HToN(uint16_t value);
   static uint16_t NToH(uint16_t value);
   static uint32_t HToN(uint32_t value);
   static uint32_t NToH(uint32_t value);
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_PLATFORM_H_