device/bluetooth: Fix = operator and copy constructor of BluetoothServiceAttributeValueBlueZ

device/bluetooth/bluez/bluetooth_service_attribute_value_bluez.h

 // 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.
 
 #ifndef DEVICE_BLUETOOTH_BLUEZ_BLUETOOTH_SERVICE_ATTRIBUTE_VALUE_BLUEZ_H_
 #define DEVICE_BLUETOOTH_BLUEZ_BLUETOOTH_SERVICE_ATTRIBUTE_VALUE_BLUEZ_H_
 
 #include <cstddef>
 #include <memory>
 #include <vector>
@@ skipping 20 matching lines @@
   using Sequence = std::vector<BluetoothServiceAttributeValueBlueZ>;
 
   BluetoothServiceAttributeValueBlueZ();
   BluetoothServiceAttributeValueBlueZ(Type type,
                                       size_t size,
                                       std::unique_ptr<base::Value> value);
   explicit BluetoothServiceAttributeValueBlueZ(
       std::unique_ptr<Sequence> sequence);
   BluetoothServiceAttributeValueBlueZ(
       const BluetoothServiceAttributeValueBlueZ& attribute);
-  BluetoothServiceAttributeValueBlueZ operator=(
+  BluetoothServiceAttributeValueBlueZ& operator=(
       const BluetoothServiceAttributeValueBlueZ& attribute);
   ~BluetoothServiceAttributeValueBlueZ();
 
   Type type() const { return type_; }
   size_t size() const { return size_; }
   const Sequence& sequence() const { return *sequence_.get(); }
   const base::Value& value() const { return *value_.get(); }
 
  private:
   Type type_;
   size_t size_;
   std::unique_ptr<base::Value> value_;
   std::unique_ptr<Sequence> sequence_;
 };
 
 }  // namespace bluez
 
 #endif  // DEVICE_BLUETOOTH_BLUEZ_BLUETOOTH_SERVICE_ATTRIBUTE_VALUE_BLUEZ_H_