Synchronize cleaning up the gesture state in the ws client

This CL attempts to fix issue 928587. The problem happens because
the gesture state remains in the window tree client although
it's cleared naturally within the window server through gesture
recognition. This can happen on window moves, since the touch
events are handled in the client first, and then the control is
shifted to the window server later.

Bug: 928587
Test: manually
Change-Id: Idf049d4aa6f418ceabd0975db292d6fa180df262
Reviewed-on: https://chromium-review.googlesource.com/c/1460444
Reviewed-by: Scott Violet <sky@chromium.org>
Reviewed-by: Tom Sepez <tsepez@chromium.org>
Commit-Queue: Jun Mukai <mukai@chromium.org>
Cr-Commit-Position: refs/heads/master@{#631032}
13 files changed