PR_IntervalNow() is not necessarily monotonic and so we shouldn't be using it
for implementing TimeStamp, especially now that it is exposed to web content
(Bug 539095).
Furthermore, it seems that the nspr implementation is being used
unintentionally on some platforms. For example, we used to use it on Android
and just now I see that it is being used in FF12 on Ubuntu.
--HG--
extra : rebase_source : cacc7f2c1d614631b93768e5979cc0820db46d54