Manage HidService lifetime in DeviceClient implementations.

device/hid/hid_service_linux.h

 // Copyright 2014 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_HID_HID_SERVICE_LINUX_H_
 #define DEVICE_HID_HID_SERVICE_LINUX_H_
 
 #include "base/compiler_specific.h"
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "device/hid/hid_device_info.h"
 #include "device/hid/hid_service.h"
 
 namespace dbus {
 class FileDescriptor;
 }
 
 namespace device {
 
 class HidConnection;
 
 class HidServiceLinux : public HidService {
  public:
   HidServiceLinux(scoped_refptr<base::SingleThreadTaskRunner> ui_task_runner);
+  ~HidServiceLinux() override;
 
   void Connect(const HidDeviceId& device_id,
                const ConnectCallback& callback) override;
 
  private:
   struct ConnectParams;
   class FileThreadHelper;
 
-  ~HidServiceLinux() override;
-
   // These functions implement the process of locating, requesting access to and
   // opening a device. Because this operation crosses multiple threads these
   // functions are static and the necessary parameters are passed as a single
   // struct.
 #if defined(OS_CHROMEOS)
   static void OnPathOpened(scoped_ptr<ConnectParams> params,
                            dbus::FileDescriptor fd);
   static void ValidateFdOnBlockingThread(scoped_ptr<ConnectParams> params,
                                          dbus::FileDescriptor fd);
 #else
   static void OpenOnBlockingThread(scoped_ptr<ConnectParams> params);
 #endif
   static void FinishOpen(scoped_ptr<ConnectParams> params);
   static void CreateConnection(scoped_ptr<ConnectParams> params);
 
   scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
   scoped_refptr<base::SingleThreadTaskRunner> file_task_runner_;
 
   // The helper lives on the FILE thread and holds a weak reference back to the
   // service that owns it.
   FileThreadHelper* helper_;
   base::WeakPtrFactory<HidServiceLinux> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(HidServiceLinux);
 };
 
 }  // namespace device
 
 #endif  // DEVICE_HID_HID_SERVICE_LINUX_H_