bluetooth: Change GetInquiryTxPower and GetInquiryRSSI to return optional.

device/bluetooth/bluetooth_classic_device_mac.mm

 // Copyright 2013 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_classic_device_mac.h"
 
 #include <string>
 
 #include "base/bind.h"
 #include "base/hash.h"
@@ skipping 130 matching lines @@
     if ([service_class_data getTypeDescriptor] ==
         kBluetoothSDPDataElementTypeDataElementSequence) {
       BluetoothUUID uuid = ExtractUuid(service_class_data);
       if (uuid.IsValid())
         uuids.push_back(uuid);
     }
   }
   return uuids;
 }
 
-int16_t BluetoothClassicDeviceMac::GetInquiryRSSI() const {
-  return kUnknownPower;
+base::Optional<int8_t> BluetoothClassicDeviceMac::GetInquiryRSSI() const {
+  return base::nullopt;
 }
 
-int16_t BluetoothClassicDeviceMac::GetInquiryTxPower() const {
-  NOTIMPLEMENTED();
-  return kUnknownPower;
+base::Optional<int8_t> BluetoothClassicDeviceMac::GetInquiryTxPower() const {
+  return base::nullopt;
 }
 
 bool BluetoothClassicDeviceMac::ExpectingPinCode() const {
   NOTIMPLEMENTED();
   return false;
 }
 
 bool BluetoothClassicDeviceMac::ExpectingPasskey() const {
   NOTIMPLEMENTED();
   return false;
@@ skipping 115 matching lines @@
   return power_level;
 }
 
 // static
 std::string BluetoothClassicDeviceMac::GetDeviceAddress(
     IOBluetoothDevice* device) {
   return CanonicalizeAddress(base::SysNSStringToUTF8([device addressString]));
 }
 
 }  // namespace device