Fix transfer length validation in Usb Api.

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

+// Copyright (c) 2013 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.usb;
+
+var genericTransfer = {
+  "direction": "in",
+  "endpoint": 1,
+  "length": -1
+};
+var controlTransfer = {
+  "index": 0,
+  "direction": "in",
+  "requestType": "standard",
+  "recipient": "device",
+  "request": 0,
+  "value": 0,
+  "length": -1
+};
+var isoTransfer = {
+  "packetLength": 0,
+  "transferInfo": genericTransfer,
+  "packets": 0
+};
+var errorMessage = 'Transfer length must be a ' +
+    'positive number less than 104,857,600.';
+var largeSize = 100*1024*1024 + 1;

[miket_OOO, 2013/01/18 20:39:03]

whitespace around binary operators

[meacer, 2013/01/18 22:48:20]

Done.

+
+function createInvalidTransferTest(usbFunction, transferInfo, transferLength) {
+  return function() {
+    genericTransfer["length"] = transferLength;
+    controlTransfer["length"] = transferLength;
+    usb.findDevices({vendorId: 0, productId: 0}, function(devices) {
+      var device = devices[0];
+      usbFunction(device, transferInfo, chrome.test.callbackFail(
+          errorMessage, function() {}));
+    });
+  };
+}
+
+var tests = [
+  createInvalidTransferTest(usb.bulkTransfer, genericTransfer, -1),
+  createInvalidTransferTest(usb.controlTransfer, controlTransfer, -1),
+  createInvalidTransferTest(usb.interruptTransfer, genericTransfer, -1),
+  createInvalidTransferTest(usb.isochronousTransfer, isoTransfer, -1),
+  createInvalidTransferTest(usb.bulkTransfer, genericTransfer, largeSize),
+  createInvalidTransferTest(usb.controlTransfer, controlTransfer, largeSize),
+  createInvalidTransferTest(usb.interruptTransfer, genericTransfer, largeSize),
+  createInvalidTransferTest(usb.isochronousTransfer, isoTransfer, largeSize)
+];
+
+chrome.test.runTests(tests);