Make the device::HidService destructor protected.

device/hid/hid_service.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_H_
 #define DEVICE_HID_HID_SERVICE_H_
 
 #include <map>
 #include <string>
 #include <vector>
 
 #include "base/memory/ref_counted.h"
 #include "base/single_thread_task_runner.h"
 #include "base/threading/thread_checker.h"
 #include "device/hid/hid_device_info.h"
 
 namespace device {
 
 class HidConnection;
 
 class HidService {
  public:
   static HidService* GetInstance(
       scoped_refptr<base::SingleThreadTaskRunner> ui_task_runner);
 
-  virtual ~HidService();
-
   // Enumerates and returns a list of device identifiers.
   virtual void GetDevices(std::vector<HidDeviceInfo>* devices);
 
   // Fills in a DeviceInfo struct with info for the given device_id.
   // Returns |true| if successful or |false| if |device_id| is invalid.
   bool GetDeviceInfo(const HidDeviceId& device_id, HidDeviceInfo* info) const;
 
   virtual scoped_refptr<HidConnection> Connect(
       const HidDeviceId& device_id) = 0;
 
  protected:
   friend class HidConnectionTest;
 
   typedef std::map<HidDeviceId, HidDeviceInfo> DeviceMap;
 
   HidService();
+  virtual ~HidService();

[Ken Rockot(use gerrit already), 2014/09/05 19:52:04]

Any reason not to make it private?

[Reilly Grant (use Gerrit), 2014/09/05 20:19:05]

Sub-classes.

 
   void AddDevice(const HidDeviceInfo& info);
   void RemoveDevice(const HidDeviceId& device_id);
   const DeviceMap& GetDevicesNoEnumerate() const;
 
   base::ThreadChecker thread_checker_;
 
  private:
+  class Destroyer;
+
   DeviceMap devices_;
 
   DISALLOW_COPY_AND_ASSIGN(HidService);
 };
 
 }  // namespace device
 
 #endif  // DEVICE_HID_HID_SERVICE_H_