UserManager stack refactoring.

components/user_manager/BUILD.gn

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 component("user_manager") {
   sources = [
     "empty_user_info.cc",
     "empty_user_info.h",
     "user_info.cc",
     "user_info.h",
@@ skipping 29 matching lines @@
       "//chromeos:chromeos",
       "//components/session_manager/core",
       "//google_apis",
       "//ui/base",
       "//ui/chromeos/resources",
       "//ui/chromeos/strings",
       "//url",
     ]
   }
 }
+
+source_set("test_support") {
+  testonly = true
+  if (is_chromeos) {
+    sources = [
+      "fake_user_manager.cc",
+      "fake_user_manager.h",
+    ]
+    deps = [
+      ":user_manager",
+      "//base",
+      "//skia",
+    ]
+  }
+}