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

device/bluetooth/bluetooth_device_win.cc

 // 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.
 
 #include "device/bluetooth/bluetooth_device_win.h"
 
 #include <memory>
 #include <string>
 
 #include "base/containers/scoped_ptr_hash_map.h"
@@ skipping 94 matching lines @@
 }
 
 bool BluetoothDeviceWin::IsConnecting() const {
   return false;
 }
 
 BluetoothDevice::UUIDList BluetoothDeviceWin::GetUUIDs() const {
   return uuids_;
 }
 
-int16_t BluetoothDeviceWin::GetInquiryRSSI() const {
-  return kUnknownPower;
+base::Optional<int8_t> BluetoothDeviceWin::GetInquiryRSSI() const {
+  return base::Optional<int8_t>();
 }
 
-int16_t BluetoothDeviceWin::GetInquiryTxPower() const {
+base::Optional<int8_t> BluetoothDeviceWin::GetInquiryTxPower() const {
   NOTIMPLEMENTED();
-  return kUnknownPower;
+  return base::Optional<int8_t>();
 }
 
 bool BluetoothDeviceWin::ExpectingPinCode() const {
   NOTIMPLEMENTED();
   return false;
 }
 
 bool BluetoothDeviceWin::ExpectingPasskey() const {
   NOTIMPLEMENTED();
   return false;
@@ skipping 262 matching lines @@
           primary_service->GetIdentifier(),
           std::unique_ptr<BluetoothRemoteGattService>(primary_service));
       adapter_->NotifyGattServiceAdded(primary_service);
     }
   }
 
   adapter_->NotifyGattServicesDiscovered(this);
 }
 
 }  // namespace device