One problem with the design from issue 582140 is that it makes it impossible to have a "lightswitch" style UI in a cross-origin iframe, and it's potentially confusing that this behavior differs based on the presence/type of iframe.
After discussion (https://groups.google.com/a/chromium.org/forum/#!topic/input-dev/kVjCq9PtGgI) we want to explore changing the intervention to consistently take a user gesture only on touchend that isn't part of a touch scroll (and never on touchstart/touchmove).
I'll try to get some UMA metrics for this into M-52, for launch consideration in M-53.
Comment 1 by rbyers@chromium.org
, May 14 2016