We use Date.now() to profile times. But, as part of the PHP porting effort, while attempting to compare PHP and node.js times for different components, @Sbailey wanted to make sure we are using similar granularity timers and we found that Date.now() is a millisecond granularity timer and is not appropriate for some of the profiling we were doing there. @Sbailey found a microsecond timer for using in the node.js transformTests.js script.

That same consideration applies to the profiling (--trace time) code we have in the parsing paths. We should replace all uses of Time.now() with a profiling api that uses the microsecond timers underneath and use that profiling api everywhere.

git grep Date.now will probably reveal all those uses.

This may also bridge some of the gap between the 'Total parse time' and 'Total profiled time` that has been bugging me since the very beginning.