GitLab

The regression (crash) was introduced when fixing an issue with hit test
source cancellation not getting propagated to the device.

In addition, already-cancelled hit test sources should throw when they
are cancelled yet again - this was also regressed.

Changes:
- fixes the crash when cancelling a hit test source on a session that
has already ended
- ensures that double-cancelling a hit test source throws
InvalidStateError (as per spec)
- add instrumentation test that would have caught the browser crash
- add WPT that would have caught the double-cancel issue

Bug: 1113461
Change-Id: I174c48d096faa902e2210e3660874dd48ca88545
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2341179Reviewed-by: Brian Sheedy <bsheedy@chromium.org>
Reviewed-by: Alexander Cooper <alcooper@chromium.org>
Commit-Queue: Piotr Bialecki <bialpio@chromium.org>
Cr-Commit-Position: refs/heads/master@{#796168}