Bluetooth: macOS: Adding logs

device/bluetooth/bluetooth_low_energy_device_mac.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 DEVICE_BLUETOOTH_BLUETOOTH_LOW_ENERGY_DEVICE_MAC_H_
 #define DEVICE_BLUETOOTH_BLUETOOTH_LOW_ENERGY_DEVICE_MAC_H_
 
 #if defined(OS_IOS)
 #import <CoreBluetooth/CoreBluetooth.h>
 #else  // !defined(OS_IOS)
@@ skipping 133 matching lines @@
   std::string hash_address_;
 
   // Increases each time -[CBPeripheral discoverServices:] is called, and
   // decreases each time DidDiscoverPrimaryServices() is called. Once the
   // value is set to 0, characteristics and properties are discovered.
   int discovery_pending_count_;
 
   DISALLOW_COPY_AND_ASSIGN(BluetoothLowEnergyDeviceMac);
 };
 
+// Stream operator for logging.
+DEVICE_BLUETOOTH_EXPORT std::ostream& operator<<(
+    std::ostream& out,
+    const BluetoothLowEnergyDeviceMac& device);
+
 }  // namespace device
 
 #endif  // DEVICE_BLUETOOTH_BLUETOOTH_LOW_ENERGY_DEVICE_MAC_H_