Previous change for the function
555ca3e7b7 (diff-bdc04e0404c2db4fd3ac5118a63eaa4a)
made use of the QueryPerformanceCounter to return microseconds values that do not repeat
as std::chrono::system_clock returned values that made auto_roll_logger_test fail.
The interface documentation does not state that we need to return
system time describing the return value as a number of microsecs since some
moment in time. However, because on Linux it is implemented using gettimeofday
various pieces of code (such as GenericRateLimiter) took advantage of that
and make use of NowMicros() as a system timestamp. Thus the previous change
broke rate_limiter_test on Windows.
In addition, the interface name NowMicros() suggests that it is actually
a timestamp so people use it as such.
This change makes use of the new system call on Windows that returns
system time with required precision. This change preserves the fix
for auto_roll_logger_test and fixes rate_limiter_test.
Note that DBTest.RateLimitingTest still fails due to a separately reported issue.
f14c3363e1