From the stack samples collected from users at startup, it seems like the following functions are very frequently hit:
clock_gettime()
gvr::ClockBase<std::__ndk1::ratio<1ll, 1000000000ll> >::now()

Without considering the samples that show wait(), this function is hit on 2% of all the samples collected for the main thread.

There is no way right now to tell yet if this is caused because of few really long gettime() calls or because of number of times chrome calls this method.