InterProcessTimeTicksConverter miscellaneous refactorings and bug fixes

This CL consists of bunch of cleanups and bug fixes:

 - LocalTimeTicks and RemoteTimeTicks are rewritten. They are now
   typedefs of SiteSpecificTimeDelta<SiteSpecificTimeLocalTag> and
   SiteSpecificTimeDelta<SiteSpecificTimeRemoteTag>, respectively, and
   have consistent methods each other.
 - Same for LocalTimeDelta and RemoteTimeDelta. Now they hold int64_t
   (via base::TimeDelta) rather than int32_t, which is good because
   int32_t lasts less than one hour.
 - This CL removes many integer operations and replaces them with
   base::TimeTicks and base::TimeDelta operations. This CL also removes
   many ToInternalValue and FromInternalValue calls which are
   deprecated.
 - InterProcessTimeTicksConverter now holds a double value for
   interpolation rather than two int64_t values as using int64_t leads
   to overflow.

Bug: 824155, 835502
Change-Id: I51ed657f0370d13b509c65324afc3af81b249e37
Reviewed-on: https://chromium-review.googlesource.com/1055171
Commit-Queue: Yutaka Hirano <yhirano@chromium.org>
Reviewed-by: Matt Menke <mmenke@chromium.org>
Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
Cr-Commit-Position: refs/heads/master@{#560511}
3 files changed