GitLab

As discussed - it's time to get rid of the GetDefaultProfile now.

BUG=322682
TEST=covered by existing unit tests

Review URL: https://codereview.chromium.org/128583002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@243963 0039d316-1c4b-4281-b951-d872f2087c98