Add DevNullHci, to facilitate fuzzing the hci layer

/*

 * Copyright 2019 The Android Open Source Project

 *

 * Licensed under the Apache License, Version 2.0 (the "License");

 * you may not use this file except in compliance with the License.

 * You may obtain a copy of the License at

 *

 *      http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

#include <stddef.h>

#include <stdint.h>

#include "hci/hci_layer.h"

#include "hci/hci_packets.h"

#include "module.h"

#include "os/fuzzing/dev_null_queue.h"

using bluetooth::hci::AclPacketView;

using bluetooth::hci::HciLayer;

using bluetooth::os::fuzzing::DevNullQueue;

namespace bluetooth {

namespace hci {

namespace fuzzing {

class DevNullHci : public Module {

 public:

  DevNullHci() : Module() {}

  void Start() override {

    hci_ = GetDependency<HciLayer>();

    aclDevNull_ = new DevNullQueue<AclPacketView>(hci_->GetAclQueueEnd(), GetHandler());

    aclDevNull_->Start();

  }

  void Stop() override {

    aclDevNull_->Stop();

    delete aclDevNull_;

  }

  void ListDependencies(ModuleList* list) override {

    list->add<HciLayer>();

  }

  static const ModuleFactory Factory;

  std::string ToString() const override {

    return "DevNullHci";

  }

 private:

  HciLayer* hci_ = nullptr;

  DevNullQueue<AclPacketView>* aclDevNull_;

};

const ModuleFactory DevNullHci::Factory = ModuleFactory([]() { return new DevNullHci(); });

}  // namespace fuzzing

}  // namespace hci

}  // namespace bluetooth