GitLab

- Whitelisting is disabled on ChromeOS by design;
- PackAndInstallExtension passes on a local ChromeOS build;
- AllowOffStore needed a fix in its waiting logic and now passes too.

BUG=404789,136397,140893

Review URL: https://codereview.chromium.org/486233002

Cr-Commit-Position: refs/heads/master@{#290805}
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@290805 0039d316-1c4b-4281-b951-d872f2087c98