Adding tests for USB extension API

chrome/test/data/extensions/api_test/usb/zero_length_transfer/test.js

+// 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.
+
+var usb = chrome.experimental.usb;
+
+function handler() {
+  var handlerObject = new Object();
+  handlerObject.onEvent = chrome.test.callbackAdded();
+  return handlerObject;
+}
+
+var tests = [
+  function zeroLengthTransfer() {
+    usb.findDevice(0, 0, handler(), function(device) {
+      var transfer = new Object();
+      transfer.direction = "out";
+      transfer.endpoint = 1;
+      transfer.data = new ArrayBuffer(0);
+      usb.bulkTransfer(device, transfer);
+    });
+  },
+];
+
+chrome.test.runTests(tests);