bluetooth: Return int8_t and use -128 for unknown tx power.

device/bluetooth/test/mock_bluetooth_device.h

 // Copyright (c) 2012 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 DEVICE_BLUETOOTH_TEST_MOCK_BLUETOOTH_DEVICE_H_
 #define DEVICE_BLUETOOTH_TEST_MOCK_BLUETOOTH_DEVICE_H_
 
 #include <stdint.h>
 
 #include <memory>
@@ skipping 31 matching lines @@
   MOCK_CONST_METHOD0(GetDeviceID, uint16_t());
   MOCK_CONST_METHOD0(GetName, base::string16());
   MOCK_CONST_METHOD0(GetDeviceType, BluetoothDevice::DeviceType());
   MOCK_CONST_METHOD0(GetAppearance, uint16_t());
   MOCK_CONST_METHOD0(IsPaired, bool());
   MOCK_CONST_METHOD0(IsConnected, bool());
   MOCK_CONST_METHOD0(IsGattConnected, bool());
   MOCK_CONST_METHOD0(IsConnectable, bool());
   MOCK_CONST_METHOD0(IsConnecting, bool());
   MOCK_CONST_METHOD0(GetUUIDs, UUIDList());
-  MOCK_CONST_METHOD0(GetInquiryRSSI, int16_t());
-  MOCK_CONST_METHOD0(GetInquiryTxPower, int16_t());
+  MOCK_CONST_METHOD0(GetInquiryRSSI, base::Optional<int8_t>());
+  MOCK_CONST_METHOD0(GetInquiryTxPower, base::Optional<int8_t>());
   MOCK_CONST_METHOD0(ExpectingPinCode, bool());
   MOCK_CONST_METHOD0(ExpectingPasskey, bool());
   MOCK_CONST_METHOD0(ExpectingConfirmation, bool());
   MOCK_METHOD1(GetConnectionInfo, void(const ConnectionInfoCallback& callback));
   MOCK_METHOD3(Connect,
                void(BluetoothDevice::PairingDelegate* pairing_delegate,
                     const base::Closure& callback,
                     const BluetoothDevice::ConnectErrorCallback&
                         error_callback));
   MOCK_METHOD3(
@@ skipping 52 matching lines @@
   std::string name_;
   std::string address_;
   BluetoothDevice::UUIDList uuids_;
 
   ScopedVector<MockBluetoothGattService> mock_services_;
 };
 
 }  // namespace device
 
 #endif  // DEVICE_BLUETOOTH_TEST_MOCK_BLUETOOTH_DEVICE_H_