Moves ImmersiveFullscreenController::SetupForTest into test class

ash/test/immersive_fullscreen_controller_test_api.h

+// Copyright 2016 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.
+
+#ifndef ASH_TEST_IMMERSIVE_FULLSCREEN_CONTROLLER_TEST_API_H_
+#define ASH_TEST_IMMERSIVE_FULLSCREEN_CONTROLLER_TEST_API_H_
+
+#include "base/macros.h"
+
+namespace ash {
+
+class ImmersiveFullscreenController;
+
+// Use by tests to get at private state of ImmersiveFullscreenController.

[msw, 2016/08/18 22:59:34]

nit: "Used" s/get at/access/

[sky, 2016/08/18 23:24:01]

Done.

+class ImmersiveFullscreenControllerTestApi {
+ public:
+  explicit ImmersiveFullscreenControllerTestApi(
+      ImmersiveFullscreenController* controller);
+  ~ImmersiveFullscreenControllerTestApi();
+
+  // Disables animations and moves the mouse so that it is not over the
+  // top-of-window views for the sake of testing.
+  void SetupForTest();
+
+ private:
+  ImmersiveFullscreenController* immersive_fullscreen_controller_;
+
+  DISALLOW_COPY_AND_ASSIGN(ImmersiveFullscreenControllerTestApi);
+};
+
+}  // namespace ash
+
+#endif  // ASH_TEST_IMMERSIVE_FULLSCREEN_CONTROLLER_TEST_API_H_