Reuse WeakFactory from U2fDevice derived classes

device/u2f/mock_u2f_device.h

 // Copyright 2017 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_U2F_MOCK_U2F_DEVICE_H_
 #define DEVICE_U2F_MOCK_U2F_DEVICE_H_
 
 #include <vector>
 
 #include "base/memory/ptr_util.h"
@@ skipping 11 matching lines @@
   MockU2fDevice();
   ~MockU2fDevice() override;
 
   MOCK_METHOD1(TryWink, void(const WinkCallback& cb));
   MOCK_METHOD0(GetId, std::string(void));
   // GMock cannot mock a method taking a std::unique_ptr<T>
   MOCK_METHOD2(DeviceTransactPtr,
                void(U2fApduCommand* command, const DeviceCallback& cb));
   void DeviceTransact(std::unique_ptr<U2fApduCommand> command,
                       const DeviceCallback& cb) override;
+  base::WeakPtr<U2fDevice> GetWeakPtr() override;
   static void TransactNoError(std::unique_ptr<U2fApduCommand> command,
                               const DeviceCallback& cb);
   static void NotSatisfied(U2fApduCommand* cmd, const DeviceCallback& cb);
   static void WrongData(U2fApduCommand* cmd, const DeviceCallback& cb);
   static void NoErrorSign(U2fApduCommand* cmd, const DeviceCallback& cb);
   static void NoErrorRegister(U2fApduCommand* cmd, const DeviceCallback& cb);
   static void WinkDoNothing(const WinkCallback& cb);
+
+ private:
+  base::WeakPtrFactory<U2fDevice> weak_factory_;
 };
 
 }  // namespace device
 
 #endif  // DEVICE_U2F_MOCK_U2F_DEVICE_H_