Implement toggle events for dialog elements
This patch implements beforetoggle and toggle events for dialog
elements. See spec issue: whatwg/html#9733
Bug: 1521813
Change-Id: I56e38230663990c8f1ed8ecd9307a6a881372605
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5238172
Commit-Queue: Joey Arhar jarhar@chromium.org
Reviewed-by: Keith Cirkel chromium@keithcirkel.co.uk
Cr-Commit-Position: refs/heads/main@{#1360795}