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

chromeos/components/tether/message_transfer_operation_unittest.cc

Index: chromeos/components/tether/message_transfer_operation_unittest.cc
diff --git a/chromeos/components/tether/message_transfer_operation_unittest.cc b/chromeos/components/tether/message_transfer_operation_unittest.cc
index ab39735677fdccd7b47ff9bae0a71ca78025d902..b564df3f6207ab3299e2253cbef8bc03f6c73993 100644
--- a/chromeos/components/tether/message_transfer_operation_unittest.cc
+++ b/chromeos/components/tether/message_transfer_operation_unittest.cc
@@ -7,6 +7,7 @@
 #include "base/timer/mock_timer.h"
 #include "chromeos/components/tether/fake_ble_connection_manager.h"
 #include "chromeos/components/tether/message_wrapper.h"
+#include "chromeos/components/tether/proto_test_util.h"
 #include "chromeos/components/tether/timer_factory.h"
 #include "components/cryptauth/remote_device_test_util.h"
 #include "testing/gmock/include/gmock/gmock.h"
@@ -147,18 +148,8 @@ class TestTimerFactory : public TimerFactory {
 };
 
 DeviceStatus CreateFakeDeviceStatus() {
-  WifiStatus wifi_status;
-  wifi_status.set_status_code(
-      WifiStatus_StatusCode::WifiStatus_StatusCode_CONNECTED);
-  wifi_status.set_ssid("Google A");
-
-  DeviceStatus device_status;
-  device_status.set_battery_percentage(75);
-  device_status.set_cell_provider("Google Fi");
-  device_status.set_connection_strength(4);
-  device_status.mutable_wifi_status()->CopyFrom(wifi_status);
-
-  return device_status;
+  return CreateTestDeviceStatus("Google Fi", 75 /* battery_percentage */,
+                                4 /* connection_strength */);
 }
 
 TetherAvailabilityResponse CreateTetherAvailabilityResponse() {