Implement document.caretPositionFromPoint with new shadowRoots argument
Spec1 for this API has changed recently to have a new argument
|shadowRoots|. Only the shadow roots that are included in the list can
be pierced by the API. Otherwise, the |CaretPosition| returned by this
API will be in the shadow host's position in it's parent.
The API is behind a runtime feature flag |CaretPositionFromPoint|.
Bug: 41487363
Change-Id: Ie467ea631819a3a8837465c7915e89785e9f5655
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5522359
Reviewed-by: Koji Ishii kojii@chromium.org
Reviewed-by: Mason Freed masonf@chromium.org
Commit-Queue: Siye Liu siliu@microsoft.com
Reviewed-by: Sanket Joshi sajos@microsoft.com
Cr-Commit-Position: refs/heads/main@{#1299340}