[CrOS Tether] Create proto_test_util.cc/h and move CreateTestDeviceStatus() there.

chromeos/components/tether/proto_test_util.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 CHROMEOS_COMPONENTS_TETHER_PROTO_TEST_UTIL_H_
+#define CHROMEOS_COMPONENTS_TETHER_PROTO_TEST_UTIL_H_
+
+#include "chromeos/components/tether/proto/tether.pb.h"
+
+namespace chromeos {
+
+namespace tether {
+
+namespace proto_test_util {
+
+// Pass these constants to CreateTestDeviceStatus() to create a proto object
+// which does not have the associated field set.
+const char kDoNotSetStringField[] = "doNotSetField";
+const int kDoNotSetIntField = -100;
+
+}  // namespace proto_test_util
+
+// Creates a DeviceStatus object using the parameters provided. If
+// |kDoNotSetStringField| or |kDoNotSetIntField| are passed, these fields will
+// not be set in the output.
+DeviceStatus CreateTestDeviceStatus(const std::string& cell_provider_name,
+                                    int battery_percentage,
+                                    int connection_strength);
+
+// Creates a DeviceStatus object using fake field values.
+DeviceStatus CreateDeviceStatusWithFakeFields();
+
+}  // namespace tether
+
+}  // namespace chromeos
+
+#endif  // CHROMEOS_COMPONENTS_TETHER_PROTO_TEST_UTIL_H_