temporary magic-file hack to tell cryptohome about chrome-login
temporary magic-file hack to tell cryptohome about chrome-login

Review URL: http://codereview.chromium.org/487004

chadversary/chromiumos.platform.login_manager,chadversary/chromiumos.platform.login_manager,joshfire/chromiumos-platform-login_manager,chadversary/chromiumos.platform.login_manager,joshfire/chromiumos-platform-login_manager,joshfire/chromiumos-platform-login_manager