Adding use_system_libusb option for third_party/libusb

chrome/browser/usb/usb_service.cc

 // Copyright (c) 2012 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.
 
 #include "chrome/browser/usb/usb_service.h"
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/stl_util.h"
 #include "chrome/browser/usb/usb_device.h"
-#include "third_party/libusb/libusb/libusb.h"
+#include "third_party/libusb/libusb.h"
 
 UsbService::UsbService() : running_(true), thread_("UsbThread") {
   libusb_init(&context_);
   thread_.Start();
   PostHandleEventTask();
 }
 
 UsbService::~UsbService() {}
 
 // TODO(gdk): There is currently no clean way to indicate to the event handler
@@ skipping 46 matching lines @@
     }
   }
 }
 
 void UsbService::PostHandleEventTask() {
   thread_.message_loop()->PostTask(FROM_HERE, base::Bind(
       &UsbService::HandleEvent, base::Unretained(this)));
 }
 
 void UsbService::HandleEvent() {
-  libusb_handle_events_completed(context_, NULL);
+  libusb_handle_events(context_);
   if (running_) {
     PostHandleEventTask();
   }
 }
 
 void UsbService::PlatformShutdown() {
   libusb_exit(context_);
 }