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

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

These classes are meant to replace OS::Ticks() and OS::TimeCurrentMillis(),
which are broken in several ways. The ElapsedTimer class implements a
stopwatch using TimeTicks::HighResNow() for high resolution, monotonic
timing.

Also fix the CpuProfile::GetStartTime() and CpuProfile::GetEndTime()
methods to actually return the time relative to the unix epoch as stated
in the documentation (previously that was relative to some arbitrary
point in time, i.e. boot time).

BUG=v8:2853
R=machenbach@chromium.org

Committed: https://code.google.com/p/v8/source/detail?r=16398

[Benedikt Meurer, 2013-08-28 12:32:02]

Hey Michael,
Fixed Windows build (verified on Jakobs machine). And renamed time folder to
platform as per offline discussion. Besides that, the same as before. PTAL
-- Benedikt

[Michael Achenbach, 2013-08-28 12:54:19]

On 2013/08/28 12:32:02, Benedikt Meurer wrote:
> Hey Michael,
> Fixed Windows build (verified on Jakobs machine). And renamed time folder to
> platform as per offline discussion. Besides that, the same as before. PTAL
> -- Benedikt

lgtm

[Benedikt Meurer, 2013-08-28 13:03:36]

Committed patchset #3 manually as r16398 (presubmit successful).

[yurys, 2013-08-28 13:35:46]

It seems to break Android Arm compilation:

  LINK(host)
/sources/chrome-git-new/v8_bleeding/out/android_arm.release/mksnapshot.arm
  AR(target)
/sources/chrome-git-new/v8_bleeding/out/android_arm.release/obj.target/tools/gyp/libv8_base.arm.a
/sources/chrome-git-new/v8_bleeding/out/android_arm.release/obj.host/v8_base.arm/src/platform/time.o:
In function `v8::internal::TimeTicks::HighResNow()':
time.cc:(.text._ZN2v88internal9TimeTicks10HighResNowEv+0x18): undefined
reference to `clock_gettime'
collect2: ld returned 1 exit status