In theory this should work in mushrome, but it currently doesn't. Need to investigate why.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/0c8c312f9e7ddcb8023b202a8b5ed559e2be3729

commit 0c8c312f9e7ddcb8023b202a8b5ed559e2be3729
Author: Elliot Glaysher <erg@chromium.org>
Date: Fri Aug 04 23:55:20 2017

Fix tab dragging on device with touch events in mus.

Bug:  705690 
Change-Id: Ia8cea4fd358f2a47923ca2f831908d5e49e4b9b4
Reviewed-on: https://chromium-review.googlesource.com/602670
Reviewed-by: Scott Violet <sky@chromium.org>
Commit-Queue: Elliot Glaysher <erg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#492179}
[modify] https://crrev.com/0c8c312f9e7ddcb8023b202a8b5ed559e2be3729/chrome/browser/ui/views/tabs/window_finder_chromeos.cc

C-M-p toggles whether touch projection circle is shown, but it appears that the coordinates are wrong. This is probably another location / root_location issue?

After dumping these events to the console: this is another case where touch events have location == root_location incorrectly.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/8b679cacf3465630201734047fd8734d711a5624

commit 8b679cacf3465630201734047fd8734d711a5624
Author: Elliot Glaysher <erg@chromium.org>
Date: Fri Aug 18 17:14:16 2017

events: Fix updating an Event's root location.

This patch was written originally by sadrul@; it's been modified just to
make unit tests pass.

Bug:  735710 ,  705690 ,  706200 ,  755780 
Change-Id: I676eba681899fe3ddd8b967382738c68449881eb
Reviewed-on: https://chromium-review.googlesource.com/619567
Commit-Queue: Elliot Glaysher <erg@chromium.org>
Reviewed-by: Sadrul Chowdhury <sadrul@chromium.org>
Cr-Commit-Position: refs/heads/master@{#495593}
[modify] https://crrev.com/8b679cacf3465630201734047fd8734d711a5624/ui/aura/mus/window_tree_client_unittest.cc
[modify] https://crrev.com/8b679cacf3465630201734047fd8734d711a5624/ui/events/event.cc
[modify] https://crrev.com/8b679cacf3465630201734047fd8734d711a5624/ui/events/event_unittest.cc

Verified this works after on device after 8b679cacf.