Adding std::ostream& operator<<(std::ostream& out, NSError* error)

device/bluetooth/bluetooth_adapter_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_adapter_mac.h"
 
 #import <IOBluetooth/objc/IOBluetoothDevice.h>
 #import <IOBluetooth/objc/IOBluetoothHostController.h>
 #include <stddef.h>
 
@@ skipping 656 matching lines @@
   BluetoothLowEnergyDeviceMac* device_mac =
       GetBluetoothLowEnergyDeviceMac(peripheral);
   if (!device_mac) {
     [low_energy_central_manager_ cancelPeripheralConnection:peripheral];
     return;
   }
   BluetoothDevice::ConnectErrorCode error_code =
       BluetoothDevice::ConnectErrorCode::ERROR_UNKNOWN;
   if (error) {
     error_code = BluetoothDeviceMac::GetConnectErrorCodeFromNSError(error);
-    VLOG(1) << "Converting Bluetooth error, domain: " << error.domain.UTF8String
-            << ", error code: " << error.code << ", to: " << error_code;
   }
   VLOG(1) << *device_mac << ": Failed to connect to peripheral with error "
-          << error;
+          << error << ", error code: " << error_code;
   device_mac->DidFailToConnectGatt(error_code);
 }
 
 void BluetoothAdapterMac::DidDisconnectPeripheral(CBPeripheral* peripheral,
                                                   NSError* error) {
   BluetoothLowEnergyDeviceMac* device_mac =
       GetBluetoothLowEnergyDeviceMac(peripheral);
   if (!device_mac) {
     [low_energy_central_manager_ cancelPeripheralConnection:peripheral];
     return;
@@ skipping 27 matching lines @@
     // Collision, two identifiers map to the same hash address.  With a 48 bit
     // hash the probability of this occuring with 10,000 devices
     // simultaneously present is 1e-6 (see
     // https://en.wikipedia.org/wiki/Birthday_problem#Probability_table).  We
     // ignore the second device by returning.
     return true;
   }
   return false;
 }
 
+DEVICE_BLUETOOTH_EXPORT std::ostream& operator<<(std::ostream& out,
+                                                 NSError* error) {
+  if (!error) {
+    return out << "no error";
+  }
+  return out << "error domain: " << base::SysNSStringToUTF8(error.domain)
+             << ", code: " << std::to_string(error.code) << ", description: "
+             << base::SysNSStringToUTF8(error.localizedDescription);
+}
+
 }  // namespace device