This is also failing: FATAL:bitset_32.h(94)] Check failed: n <= 31U (2147483647 vs. 31)

Assigning to Dennis to take a look. Dennis, assign back if this isn't your code

This breaks stylus support since in Android id's can't be > 31. 

In ozone's Event Factory, the reported IDs seem perfectly fine: 0, 1, 2, 3 for touch and for stylus as well. 

Between that and the exo event handler there must be some touch id transformation going on, since there the id seem to be substracted by 1.
1 turns to 0. 0 turns to -1 or 2147483647. 

This also seems to break multi-touch support in exo and other parts of the system as well:

Pinch zooming broken on tip of tree: https://bugs.chromium.org/p/chromium/issues/detail?id=696099

Other validators broken: https://bugs.chromium.org/p/chromium/issues/detail?id=696099

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/de104fb57e491bef3f2883f5a9100b9524fb0e3c

commit de104fb57e491bef3f2883f5a9100b9524fb0e3c
Author: lanwei <lanwei@chromium.org>
Date: Thu Mar 02 21:22:49 2017

Make pinch zoom work on chromeos by setting touch id correctly

In EventFactoryEvdev, the touch id is reset to default value 0 after setting a PointerDetails object,
which causes two touch pointer have the same id, and pinch zoom does not work.

We need to set the touch id in PointerDetails and check in all the set_pointer_details
to make sure that id is not reset to default.

BUG= 695905 , 696369 

Review-Url: https://codereview.chromium.org/2720133002
Cr-Commit-Position: refs/heads/master@{#454378}

[modify] https://crrev.com/de104fb57e491bef3f2883f5a9100b9524fb0e3c/ui/events/event.cc
[modify] https://crrev.com/de104fb57e491bef3f2883f5a9100b9524fb0e3c/ui/events/event.h
[modify] https://crrev.com/de104fb57e491bef3f2883f5a9100b9524fb0e3c/ui/events/event_unittest.cc
[modify] https://crrev.com/de104fb57e491bef3f2883f5a9100b9524fb0e3c/ui/events/ozone/evdev/event_factory_evdev.cc