Revert "login: need-arc-migration-policy-check flag"

This reverts commit 69a3ec7f36f11a0fddc6e6b3083ebc1276358753.

Reason for revert: This functionality was needed for device
policy implemented in M-60. Starting from M-61 it is covered
by an user policy and the flag is not needed.

Original change's description:
> login: need-arc-migration-policy-check flag
>
> If arc_policy_migration_check USE flag is enabled, set
> need-arc-migration-policy-check.
>
> BUG=chromium:722371
> TEST=none
>
> Change-Id: I8741984abc35669edbe8d443d4334d98005a7d8b
> Reviewed-on: https://chromium-review.googlesource.com/533236
> Commit-Ready: Igor <igorcov@chromium.org>
> Tested-by: Igor <igorcov@chromium.org>
> Reviewed-by: Dan Erat <derat@chromium.org>

Bug: chromium:725493
Change-Id: I1fa76bb683c6019ebff9ae47472a44d4a21182ad
Reviewed-on: https://chromium-review.googlesource.com/602150
Commit-Ready: Igor <igorcov@chromium.org>
Tested-by: Igor <igorcov@chromium.org>
Reviewed-by: Dan Erat <derat@chromium.org>
(cherry picked from commit 4016485c26034ae9726d408f0c242abb87896faa)
Reviewed-on: https://chromium-review.googlesource.com/626125
Commit-Queue: Igor <igorcov@chromium.org>
diff --git a/login_manager/chrome_setup.cc b/login_manager/chrome_setup.cc
index 2f78764..40e9e95 100644
--- a/login_manager/chrome_setup.cc
+++ b/login_manager/chrome_setup.cc
@@ -119,8 +119,6 @@
     builder->AddArg("--enable-arc-oobe-optin");
   if (builder->UseFlagIsSet("arc_always_start_with_no_play_store"))
     builder->AddArg("--arc-start-mode=always-start-with-no-play-store");
-  if (builder->UseFlagIsSet("arc_migration_policy_check"))
-    builder->AddArg("--need-arc-migration-policy-check");
 }
 
 // Blatantly copied from //components/crx_file/id_util.cc.