Linux: fix build with gnome-keyring on Aura.

This is upstreaming a Gentoo Linux patch.

BUG=none
R=erg@chromium.org

Review URL: https://codereview.chromium.org/62173003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@235446 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 235446