Ensure libusb_close is called from the FILE thread.

device/usb/usb_device_handle_impl.cc

Index: device/usb/usb_device_handle_impl.cc
diff --git a/device/usb/usb_device_handle_impl.cc b/device/usb/usb_device_handle_impl.cc
index 716c6c196611213a625c5ce329cb0945e1c835a0..cf6ebfb13efd51c91b81f4ca69934e00a132a617 100644
--- a/device/usb/usb_device_handle_impl.cc
+++ b/device/usb/usb_device_handle_impl.cc
@@ -782,8 +782,14 @@ UsbDeviceHandleImpl::UsbDeviceHandleImpl(
 
 UsbDeviceHandleImpl::~UsbDeviceHandleImpl() {
   // This class is RefCountedThreadSafe and so the destructor may be called on
-  // any thread.
-  libusb_close(handle_);
+  // any thread. libusb is not safe to reentrancy so be sure not to try to close
+  // the device from inside a transfer completion callback.
+  if (blocking_task_runner_->RunsTasksOnCurrentThread()) {
+    libusb_close(handle_);
+  } else {
+    blocking_task_runner_->PostTask(FROM_HERE,
+                                    base::Bind(&libusb_close, handle_));
+  }
 }
 
 void UsbDeviceHandleImpl::SetConfigurationOnBlockingThread(