GitLab

Converts ModelAddedCallback and ModelRemovedCallback to base::Repeating
Callbacks to match their usage. Removes the corresponding entry from
PRESUBMIT.py

Bug: 1007635
Change-Id: I10393eea74ff16ba86f5e7118765557fca770028
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2303877
Commit-Queue: Alexander Cooper <alcooper@chromium.org>
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Cr-Commit-Position: refs/heads/master@{#790982}