tree 4742aacb220f2a1f322c85283ea6c391a956c599
parent 4c5703d9287e806d37ba26a100a403fd5e7add61
author George Steel <gtsteel@google.com> 1597789091 -0700
committer Blink WPT Bot <blink-w3c-test-autoroller@chromium.org> 1597791584 -0700

Perpare to fix cancelling when unsetting transition and fix metric

Add logic to distinguish between transitions which should (base
computed style changes) and shouldn't be cancelled when transition is
completely unset (as the default is all 0s). Currently, both are still
cancelled, the same as the old behaviour, but the histogram
kCSSTransitionCancelledByRemovingStyle is now only incremented when
transitions are cancelled incorrectly.

Add WPT for not cancelling transitions then unsetting transition
property, fix web_tests to cancel transitions by setting transition to
none instead of unsetting.

Bug: 934700
Change-Id: Iaf4bf324e6e2bd6ca22a66fd8ae2320620a874dc
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2363173
Reviewed-by: Kevin Ellis <kevers@chromium.org>
Commit-Queue: George Steel <gtsteel@chromium.org>
Cr-Commit-Position: refs/heads/master@{#799336}