GitLab

Unregister BookmarkImageService observer from BookmarkModel in the
Shutdown method instead of the destructor to follow the two step
shutdown of the profile.

Fix a typo in the EnhancedBookmarkModel override of KeyedService
Shutdown method (could have been caught by using the OVERRIDE keyword).

BUG=None

Review URL: https://codereview.chromium.org/588233002

Cr-Commit-Position: refs/heads/master@{#296009}