arc: bluetooth: Replace nullptr with "" for mojo::String

components/arc/bluetooth/arc_bluetooth_bridge.cc

 // Copyright 2016 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 "components/arc/bluetooth/arc_bluetooth_bridge.h"
 
 #include <bluetooth/bluetooth.h>
 #include <fcntl.h>
 #include <stddef.h>
 #include <sys/socket.h>
@@ skipping 1838 matching lines @@
                                         const BluetoothDevice* device) const {
   mojo::Array<mojom::BluetoothPropertyPtr> properties;
 
   if (!device) {
     return properties;
   }
 
   if (type == mojom::BluetoothPropertyType::ALL ||
       type == mojom::BluetoothPropertyType::BDNAME) {
     mojom::BluetoothPropertyPtr btp = mojom::BluetoothProperty::New();
-    btp->set_bdname(device->GetName() ? device->GetName().value() : nullptr);
+    btp->set_bdname(device->GetName() ? device->GetName().value() : "");
     properties.push_back(std::move(btp));
   }
   if (type == mojom::BluetoothPropertyType::ALL ||
       type == mojom::BluetoothPropertyType::BDADDR) {
     mojom::BluetoothPropertyPtr btp = mojom::BluetoothProperty::New();
     btp->set_bdaddr(mojom::BluetoothAddress::From(device->GetAddress()));
     properties.push_back(std::move(btp));
   }
   if (type == mojom::BluetoothPropertyType::ALL ||
       type == mojom::BluetoothPropertyType::UUIDS) {
@@ skipping 150 matching lines @@
     mojom::BluetoothAdvertisingDataPtr flags =
         mojom::BluetoothAdvertisingData::New();
     flags->set_flags(device->GetAdvertisingDataFlags().value());
     advertising_data.push_back(std::move(flags));
   }
 
   // Local Name
   mojom::BluetoothAdvertisingDataPtr local_name =
       mojom::BluetoothAdvertisingData::New();
   local_name->set_local_name(device->GetName() ? device->GetName().value()
-                                               : nullptr);
+                                               : "");
   advertising_data.push_back(std::move(local_name));
 
   // Service UUIDs
   const BluetoothDevice::UUIDSet& uuid_set = device->GetUUIDs();
   if (uuid_set.size() > 0) {
     mojom::BluetoothAdvertisingDataPtr service_uuids =
         mojom::BluetoothAdvertisingData::New();
     service_uuids->set_service_uuids(mojo::Array<BluetoothUUID>::From(
         std::vector<BluetoothUUID>(uuid_set.begin(), uuid_set.end())));
     advertising_data.push_back(std::move(service_uuids));
@@ skipping 125 matching lines @@
   sdp_bluetooth_instance->OnGetSdpRecords(
       status, std::move(remote_addr), target_uuid,
       mojo::Array<mojom::BluetoothSdpRecordPtr>::New(0));
 }
 
 bool ArcBluetoothBridge::CalledOnValidThread() {
   return thread_checker_.CalledOnValidThread();
 }
 
 }  // namespace arc