GitLab

Caused by r549433, which swapped the initialization order of the AppMenu
and AppMenuModel. By constructing the AppMenuModel first, the old one
was being destroyed, being outlived by its AppMenu (holding a raw
pointer). Adds a reset(), ensuring the AppMenu is destroyed first.

Bug: 831504
No-Try: true
Change-Id: I3d155b11aa2490537fc6baa9fbbf2bdb057e8090
Reviewed-on: https://chromium-review.googlesource.com/1006739
Commit-Queue: Matt Giuca <mgiuca@chromium.org>
Reviewed-by: Bret Sepulveda <bsep@chromium.org>
Cr-Commit-Position: refs/heads/master@{#550022}