Tell the kernel to discard USB requests when they time out.

device/usb/usb_device_handle_usbfs.h

Index: device/usb/usb_device_handle_usbfs.h
diff --git a/device/usb/usb_device_handle_usbfs.h b/device/usb/usb_device_handle_usbfs.h
index 4cfc1851a3875a3f3b0abb381885e0c3bad3f943..47ae15526f048c1467e7899506f4448cb1497811 100644
--- a/device/usb/usb_device_handle_usbfs.h
+++ b/device/usb/usb_device_handle_usbfs.h
@@ -139,8 +139,10 @@ class UsbDeviceHandleUsbfs : public UsbDeviceHandle {
       const UsbDeviceHandle::IsochronousTransferCallback& callback,
       UsbTransferStatus status);
   void SetUpTimeoutCallback(Transfer* transfer, unsigned int timeout);
-
-  static void CancelTransfer(Transfer* transfer, UsbTransferStatus status);
+  std::unique_ptr<Transfer> RemoveFromTransferList(Transfer* transfer);
+  void CancelTransfer(Transfer* transfer, UsbTransferStatus status);
+  void DiscardUrbBlocking(Transfer* transfer);
+  void UrbDiscarded(Transfer* transfer);
 
   scoped_refptr<UsbDevice> device_;
   base::ScopedFD fd_;