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

device/bluetooth/bluetooth_device.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.h"
 
 #include <memory>
 #include <string>
 
 #include "base/memory/ptr_util.h"
@@ skipping 11 matching lines @@
 
 BluetoothDevice::BluetoothDevice(BluetoothAdapter* adapter)
     : adapter_(adapter),
       gatt_services_discovery_complete_(false),
       services_data_(new base::DictionaryValue()) {}
 
 BluetoothDevice::~BluetoothDevice() {
   DidDisconnectGatt();
 }
 
-BluetoothDevice::ConnectionInfo::ConnectionInfo()
-    : rssi(kUnknownPower),
-      transmit_power(kUnknownPower),
-      max_transmit_power(kUnknownPower) {}
+BluetoothDevice::ConnectionInfo::ConnectionInfo() {}
 
 BluetoothDevice::ConnectionInfo::ConnectionInfo(
-    int rssi, int transmit_power, int max_transmit_power)
+    const base::Optional<int8_t>& rssi,
+    const base::Optional<int8_t>& transmit_power,
+    const base::Optional<int8_t>& max_transmit_power)
     : rssi(rssi),
       transmit_power(transmit_power),
       max_transmit_power(max_transmit_power) {}
 
 BluetoothDevice::ConnectionInfo::~ConnectionInfo() {}
 
 base::string16 BluetoothDevice::GetName() const {
   std::string name = GetDeviceName();
   if (!name.empty()) {
     return base::UTF8ToUTF16(name);
@@ skipping 332 matching lines @@
                       base::BinaryValue::CreateWithCopiedBuffer(buffer, size));
 }
 
 void BluetoothDevice::Pair(PairingDelegate* pairing_delegate,
                            const base::Closure& callback,
                            const ConnectErrorCallback& error_callback) {
   NOTREACHED();
 }
 
 }  // namespace device