chromeos: Introduce ash::SystemTrayTestApi

ash/system/tray/system_tray_test_api.h

+// Copyright 2017 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_SYSTEM_TRAY_SYSTEM_TRAY_TEST_API_H_
+#define ASH_SYSTEM_TRAY_SYSTEM_TRAY_TEST_API_H_
+
+#include "ash/system/tray/system_tray.h"
+#include "base/macros.h"
+
+namespace ash {
+
+// Use by tests to access private state of SystemTray.
+class SystemTrayTestApi {
+ public:
+  explicit SystemTrayTestApi(SystemTray* tray) : tray_(tray) {}
+  ~SystemTrayTestApi() = default;
+
+  TrayAccessibility* tray_accessibility() { return tray_->tray_accessibility_; }
+  TrayCast* tray_cast() { return tray_->tray_cast_; }
+  TrayEnterprise* tray_enterprise() { return tray_->tray_enterprise_; }
+  TrayNetwork* tray_network() { return tray_->tray_network_; }
+  TraySupervisedUser* tray_supervised_user() {
+    return tray_->tray_supervised_user_;
+  }
+  TraySystemInfo* tray_system_info() { return tray_->tray_system_info_; }
+  TrayTiles* tray_tiles() { return tray_->tray_tiles_; }
+
+ private:
+  SystemTray* tray_;

[xiyuan, 2017/06/07 16:29:08]

nit: SystemTray* const since |tray_| should never change during
SystemTrayTestApi's lifetime.

[James Cook, 2017/06/07 16:35:53]

Done.

+
+  DISALLOW_COPY_AND_ASSIGN(SystemTrayTestApi);
+};
+
+}  // namespace ash
+
+#endif  // ASH_SYSTEM_TRAY_SYSTEM_TRAY_TEST_API_H_