ImmediateInterpreter: replace origin_timestamps_ with metrics

Origin timestamps were already being collected by FingerMetrics, so
removing origin_timestamps_ reduces duplication and should make it
easier to separate out the tap-to-click logic later.

BUG=b:245989146
TEST=run unit tests on Android; try tapping to click before and after
     the change, check there's no behaviour difference

Change-Id: I5e0afb9e4a640b15de1255e3d3d27a9e9eb12d54
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/gestures/+/4966486
Reviewed-by: Denis Brockus <dbrockus@chromium.org>
Code-Coverage: Zoss <zoss-cl-coverage@prod.google.com>
Tested-by: Harry Cutts <hcutts@chromium.org>
Commit-Queue: Harry Cutts <hcutts@chromium.org>
5 files changed