Destroy DeviceImpl when the underlying UsbDevice is disconnected.

device/usb/mojo/device_impl.h

 // Copyright 2015 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_MOJO_DEVICE_IMPL_H_
 #define DEVICE_USB_MOJO_DEVICE_IMPL_H_
 
 #include <stdint.h>
 
 #include "base/callback_forward.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/weak_ptr.h"
+#include "base/scoped_observer.h"
 #include "device/usb/public/interfaces/device.mojom.h"
 #include "device/usb/public/interfaces/permission_provider.mojom.h"
+#include "device/usb/usb_device.h"
 #include "device/usb/usb_device_handle.h"
 #include "mojo/public/cpp/bindings/binding.h"
 #include "mojo/public/cpp/bindings/callback.h"
 #include "mojo/public/cpp/bindings/interface_request.h"
 
 namespace net {
 class IOBuffer;
 }
 
 namespace device {
 namespace usb {
 
 // Implementation of the public Device interface. Instances of this class are
 // constructed by DeviceManagerImpl and are strongly bound to their MessagePipe
 // lifetime.
-class DeviceImpl : public Device {
+class DeviceImpl : public Device, public device::UsbDevice::Observer {
  public:
   DeviceImpl(scoped_refptr<UsbDevice> device,
              PermissionProviderPtr permission_provider,
              mojo::InterfaceRequest<Device> request);
   ~DeviceImpl() override;
 
  private:
   // Closes the device if it's open. This will always set |device_handle_| to
   // null.
   void CloseHandle();
@@ skipping 45 matching lines @@
       mojo::Array<uint32_t> packet_lengths,
       uint32_t timeout,
       const IsochronousTransferInCallback& callback) override;
   void IsochronousTransferOut(
       uint8_t endpoint_number,
       mojo::Array<uint8_t> data,
       mojo::Array<uint32_t> packet_lengths,
       uint32_t timeout,
       const IsochronousTransferOutCallback& callback) override;
 
-  mojo::Binding<Device> binding_;
+  // device::UsbDevice::Observer implementation:
+  void OnDeviceRemoved(scoped_refptr<device::UsbDevice>) override;
 
   scoped_refptr<UsbDevice> device_;
+  ScopedObserver<device::UsbDevice, device::UsbDevice::Observer> observer_;
+
   // The device handle. Will be null before the device is opened and after it
   // has been closed.
   scoped_refptr<UsbDeviceHandle> device_handle_;
   PermissionProviderPtr permission_provider_;
 
+  mojo::Binding<Device> binding_;
   base::WeakPtrFactory<DeviceImpl> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(DeviceImpl);
 };
 
 }  // namespace usb
 }  // namespace device
 
 #endif  // DEVICE_USB_MOJO_DEVICE_IMPL_H_