Chrome implements a proposed variant (https://github.com/w3c/pointerevents/issues/8) of the Pointer Events spec which avoids hit-tests on every touch movement.  Edge plans to add a flag that implements this model (to help analyze the web compat impact).  Assuming it's not more than a couple days of engineering work, we should also add a flag to switch to the Edge model.  I.e. avoid doing the implicit capture on touch, and have explicit capture send the boundary events.

We can use this in our compat testing to quickly confirm whether any site problems are due to this proposed change.