Stop the OverviewButton from appearing on the Add-User screen

ash/system/overview/overview_button_tray_unittest.cc

Index: ash/system/overview/overview_button_tray_unittest.cc
diff --git a/ash/system/overview/overview_button_tray_unittest.cc b/ash/system/overview/overview_button_tray_unittest.cc
index a7e6a3e17fe4ba9c87a6e654e576fc0b7ae8eff2..702f31de80da829705c3b9d4985b1032a86afc78 100644
--- a/ash/system/overview/overview_button_tray_unittest.cc
+++ b/ash/system/overview/overview_button_tray_unittest.cc
@@ -14,7 +14,9 @@
 #include "ash/system/status_area_widget.h"
 #include "ash/system/user/login_status.h"
 #include "ash/test/ash_test_base.h"
+#include "ash/test/ash_test_helper.h"
 #include "ash/test/status_area_widget_test_helper.h"
+#include "ash/test/test_session_state_delegate.h"
 #include "ash/wm/maximize_mode/maximize_mode_controller.h"
 #include "ash/wm/overview/window_selector_controller.h"
 #include "base/command_line.h"
@@ -51,6 +53,8 @@ class OverviewButtonTrayTest : public test::AshTestBase {
 
   void SetUp() override;
 
+  void UpdateSessionsState();
+
  protected:
   views::ImageView* GetImageView(OverviewButtonTray* tray) {
     return tray->icon_;
@@ -68,6 +72,11 @@ void OverviewButtonTrayTest::SetUp() {
   AshTestBase::SetUp();
 }
 
+void OverviewButtonTrayTest::UpdateSessionsState() {
+  GetTray()->SessionStateChanged(
+      ash_test_helper()->GetTestSessionStateDelegate()->GetSessionState());
+}
+
 // Ensures that creation doesn't cause any crashes and adds the image icon.
 TEST_F(OverviewButtonTrayTest, BasicConstruction) {
   EXPECT_TRUE(GetImageView(GetTray()) != NULL);
@@ -178,6 +187,12 @@ TEST_F(OverviewButtonTrayTest, VisibilityChangesForLoginStatus) {
   SetSessionStarted(true);
   Shell::GetInstance()->UpdateAfterLoginStatusChange(user::LOGGED_IN_USER);
   EXPECT_TRUE(GetTray()->visible());
+  SetUserAddingScreenRunning(true);
+  UpdateSessionsState();
+  EXPECT_FALSE(GetTray()->visible());
+  SetUserAddingScreenRunning(false);
+  UpdateSessionsState();
+  EXPECT_TRUE(GetTray()->visible());
   Shell::GetInstance()->maximize_mode_controller()->
       EnableMaximizeModeWindowManager(false);
 }