ImmediateInterpreter: fix subtraction of non_gs_fingers from gs_fingers

While working on an unrelated refactoring, I noticed that new_gs_fingers
in SyncInterpretImpl was apparently unused. Looking at the history, it
seems that https://crrev.com/c/3732128 (which replaced the home-made set
implementation with one from the standard library) contained an error in
the refactoring of this code: the call to SetSubtract was replaced with
a call to std::set_difference that put the resulting set in
new_gs_fingers, but the code below was not updated to use
new_gs_fingers instead of gs_fingers.

BUG=b:200072742
TEST=cros_workon_make --board=volteer --test chromeos-base/gestures;
     touch regression tests

Change-Id: Icb72458493c1a342f5d68ce51e465268d881fc18
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/gestures/+/4742305
Reviewed-by: Henry Barnor <hbarnor@chromium.org>
Auto-Submit: Harry Cutts <hcutts@chromium.org>
Commit-Queue: Denis Brockus <dbrockus@chromium.org>
Code-Coverage: Zoss <zoss-cl-coverage@prod.google.com>
Commit-Queue: Harry Cutts <hcutts@chromium.org>
Tested-by: Harry Cutts <hcutts@chromium.org>
Reviewed-by: Denis Brockus <dbrockus@chromium.org>
1 file changed