Skip post-login screens for UserCloudPolicyManagerTest

UserCloudPolicyManagerTest didn't work for chrome branded builds,
because it tried to show sync consent screen on fake user login, and
therefore made browser tests to hang waiting for user interaction.

This commit adds an option to skip all post-login screens.

Bug: 976987
Change-Id: Ie42980bc4791efe9a455780c5dff9ec8c8abbd76
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1833465Reviewed-by: Sergey Poromov <poromov@chromium.org>
Commit-Queue: Oleg Davydov <burunduk@chromium.org>
Cr-Commit-Position: refs/heads/master@{#701638}

chrome/browser/chromeos/policy/user_cloud_policy_manager_chromeos_browsertest.cc

@@ -22,6 +22,7 @@
 #include "chrome/common/chrome_features.h"
 #include "chrome/test/base/mixin_based_in_process_browser_test.h"
 #include "chromeos/assistant/buildflags.h"
+#include "chromeos/constants/chromeos_switches.h"
 #include "components/arc/arc_features.h"
 #include "components/arc/arc_prefs.h"
 #include "components/policy/core/browser/browser_policy_connector.h"
@@ -69,6 +70,11 @@ class UserCloudPolicyManagerTest
     MixinBasedInProcessBrowserTest::TearDown();
   }
 
+  void SetUpCommandLine(base::CommandLine* command_line) override {
+    command_line->AppendSwitch(chromeos::switches::kOobeSkipPostLogin);
+    MixinBasedInProcessBrowserTest::SetUpCommandLine(command_line);
+  }
+
   // Sets up fake GAIA for specified user login, and requests login for the user
   // (using LoggedInUserMixin).
   void StartUserLogIn(bool wait_for_active_session) {

testing/buildbot/filters/chromeos.browser_tests.filter

@@ -39,13 +39,3 @@
 # TODO(crbug.com/977749): Enable this.
 -TestAsNormalAndGuestUser/SpokenFeedbackTest.OverviewMode/0
 -TestAsNormalAndGuestUser/SpokenFeedbackTest.OverviewMode/1
-
-# TODO(crbug.com/976987): Enable this.
--UserCloudPolicyManagerTest.ErrorLoadingPolicyForUnmanagedUser/0
--UserCloudPolicyManagerTest.ErrorLoadingPolicyForUnmanagedUser/1
--UserCloudPolicyManagerTest.NoPolicyForNonEnterpriseUser/0
--UserCloudPolicyManagerTest.NoPolicyForNonEnterpriseUser/1
--UserCloudPolicyManagerTest.PolicyForChildUser/0
--UserCloudPolicyManagerTest.PolicyForChildUser/1
--UserCloudPolicyManagerTest.StartSession/0
--UserCloudPolicyManagerTest.StartSession/1