GitLab

Fork relevant assets (as follow-up to CL 2855883005) so that the new
design of lock screen can be implemented in tandem with login screen.

The recently added flag (kShowMdLogin) is reserved for views-based login
and lock screen as they are being implemented.

The new flag added by this CL (kShowNonViewMdLogin) is a temporary flag
used until the views-based screens become available.

The two flags should not be used together.

BUG=718174
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:closure_compilation

Review-Url: https://codereview.chromium.org/2874303003
Cr-Commit-Position: refs/heads/master@{#471449}