GitLab

Other bookmarks observer might make their own changes on add, triggering updates
before the add call arrives. Be resilient against this.

BUG=369728

Review URL: https://codereview.chromium.org/277033002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@269645 0039d316-1c4b-4281-b951-d872f2087c98