Allow passing timestamps to Timing.mark.
Allow passing timestamps to Timing.mark.

Timing.mark() currently creates marks and measures using the performance API,
and also reports measures to Google Analytics.
V2SPA uses Timing.mark() to measure various types of events, including
navigation events such as performance.timing, which provides timestamps.
This CL allows V2SPA to report performance.timing events to Google Analytics.
Timing.mark() can't create performance API marks/measures with timestamps, but
it can still report durations to Google Analytics.
When Google Analytics is unavailable, Timing.mark() optionally logs timestamp
events to the console since they would otherwise disappear.

Bug: catapult:#4461
Change-Id: Iabfafaa6325f24d4cc5b4d1cf7e8bb59fa4ac57f
Reviewed-on: https://chromium-review.googlesource.com/1067589
Reviewed-by: Ethan Kuefner <b3258c73b307e35b2725bc68d7434c38b3a2b146@chromium.org>
Commit-Queue: Ben Hayden <d3ffe0e065c2328e497bb32a07f4dcb29138ef5b@chromium.org>

catapult-project/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult