Remove MessageLoop destruction observer from //device/usb

device/usb/usb_device_handle_usbfs.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_USB_USB_DEVICE_HANDLE_USBFS_H_
 #define DEVICE_USB_USB_DEVICE_HANDLE_USBFS_H_
 
 #include <list>
 #include <map>
 #include <memory>
@@ skipping 86 matching lines @@
   struct Transfer;
   struct InterfaceInfo {
     uint8_t alternate_setting;
   };
   struct EndpointInfo {
     UsbTransferType type;
     const UsbInterfaceDescriptor* interface;
   };
 
   virtual void CloseBlocking();
-  void SetConfigurationBlocking(int configuration_value,
-                                const ResultCallback& callback);
   void SetConfigurationComplete(int configuration_value,
                                 bool success,
                                 const ResultCallback& callback);
-  void ReleaseInterfaceBlocking(int interface_number,
-                                const ResultCallback& callback);
   void ReleaseInterfaceComplete(int interface_number,
                                 const ResultCallback& callback);
-  void SetInterfaceBlocking(int interface_number,
-                            int alternate_setting,
-                            const ResultCallback& callback);
-  void ResetDeviceBlocking(const ResultCallback& callback);
-  void ClearHaltBlocking(uint8_t endpoint_address,
-                         const ResultCallback& callback);
   void IsochronousTransferInternal(uint8_t endpoint_address,
                                    scoped_refptr<net::IOBuffer> buffer,
                                    size_t total_length,
                                    const std::vector<uint32_t>& packet_lengths,
                                    unsigned int timeout,
                                    const IsochronousTransferCallback& callback);
   void GenericTransferInternal(
       UsbEndpointDirection direction,
       uint8_t endpoint_number,
       scoped_refptr<net::IOBuffer> buffer,
@@ skipping 21 matching lines @@
 
   // Maps claimed interfaces by interface number to their current alternate
   // setting.
   std::map<uint8_t, InterfaceInfo> interfaces_;
 
   // Maps endpoints (by endpoint address) to the interface they are a part of.
   // Only endpoints of currently claimed and selected interface alternates are
   // included in the map.
   std::map<uint8_t, EndpointInfo> endpoints_;
 
-  // Helper object owned by the blocking task thread. It will be freed if that
-  // thread's message loop is destroyed but can also be freed by this class on
-  // destruction.
-  FileThreadHelper* helper_;
+  // Helper object exists on the blocking task thread and must be freed there.
+  std::unique_ptr<FileThreadHelper> helper_;
 
   std::list<std::unique_ptr<Transfer>> transfers_;
 };
 
 }  // namespace device
 
 #endif  // DEVICE_USB_USB_DEVICE_HANDLE_USBFS_H_