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

content/common/bluetooth/bluetooth_device.h

 // Copyright 2015 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 CONTENT_COMMON_BLUETOOTH_BLUETOOTH_DEVICE_H_
 #define CONTENT_COMMON_BLUETOOTH_BLUETOOTH_DEVICE_H_
 
 #include <stdint.h>
 
 #include <string>
@@ skipping 10 matching lines @@
   BluetoothDevice();
   BluetoothDevice(const std::string& id,
                   const base::string16& name,
                   int8_t tx_power,
                   int8_t rssi,
                   const std::vector<std::string>& uuids);
   ~BluetoothDevice();
 
   static std::vector<std::string> UUIDsFromBluetoothUUIDs(
       const device::BluetoothDevice::UUIDList& uuid_list);
-  // 127 is used as Unknown Power. According to the Bluetooth spec valid powers
-  // are between [-127, 127]. Anything outside this range will be considered
-  // Unknown Power.
-  static int8_t ValidatePower(int16_t power);
-  // TODO(ortuno): RSSI Unknown and Tx Power Unknown should have different
-  // values. Add kUnknownTxPower when implemented: http://crbug.com/551572
-  const static int8_t kUnknownPower = 127;
 
   std::string id;
   base::string16 name;
   int8_t tx_power;
   int8_t rssi;
   std::vector<std::string> uuids;  // 128bit UUIDs with dashes. 36 chars.
 };
 
 }  // namespace content
 
 #endif  // CONTENT_COMMON_BLUETOOTH_BLUETOOTH_DEVICE_H_