GitLab

- Move constants into *_constants.{cc,h}.
- Remove unused constants.
- Lay foundation for detailed process exit codes.

BUG=385419

Review URL: https://codereview.chromium.org/365143002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@282032 0039d316-1c4b-4281-b951-d872f2087c98