Moves ash::user::LoginStatus to ash/common

ash/system/user/tray_user_unittest.cc

Index: ash/system/user/tray_user_unittest.cc
diff --git a/ash/system/user/tray_user_unittest.cc b/ash/system/user/tray_user_unittest.cc
index d0ea56675d182749f71b9a8580df6a201b3bf106..d851271e8671da01c0f6686c8a4d3e928c012855 100644
--- a/ash/system/user/tray_user_unittest.cc
+++ b/ash/system/user/tray_user_unittest.cc
@@ -124,10 +124,10 @@ void TrayUserTest::ClickUserItem(ui::test::EventGenerator* generator,
 // Make sure that we show items for all users in the tray accordingly.
 TEST_F(TrayUserTest, CheckTrayItemSize) {
   InitializeParameters(1, false);
-  tray_user(0)->UpdateAfterLoginStatusChangeForTest(user::LOGGED_IN_GUEST);
+  tray_user(0)->UpdateAfterLoginStatusChangeForTest(LoginStatus::GUEST);
   gfx::Size size = tray_user(0)->GetLayoutSizeForTest();
   EXPECT_EQ(kTrayItemSize, size.height());
-  tray_user(0)->UpdateAfterLoginStatusChangeForTest(user::LOGGED_IN_USER);
+  tray_user(0)->UpdateAfterLoginStatusChangeForTest(LoginStatus::USER);
   size = tray_user(0)->GetLayoutSizeForTest();
   EXPECT_EQ(kTrayItemSize, size.height());
 }