Add RemoveAllMenuItems().

This allows callers that want this to be both clearer and more efficient.

Bug: none
Change-Id: Ida11ebd5e131b250aeaf6a505be7d5176ff3e472
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1525279
Commit-Queue: Peter Kasting <pkasting@chromium.org>
Commit-Queue: Trent Apted <tapted@chromium.org>
Auto-Submit: Peter Kasting <pkasting@chromium.org>
Reviewed-by: Trent Apted <tapted@chromium.org>
Cr-Commit-Position: refs/heads/master@{#641075}
4 files changed