Update device/usb and its Mojo interface for variable size ISO packets.

extensions/test/data/api_test/usb/transfer_failure/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.usb;
 
 function createErrorTest(resultCode, errorMessage) {
   return function() {
     usb.findDevices({vendorId: 0, productId: 0}, function(devices) {
       var device = devices[0];
       var transfer = new Object();
       transfer.direction = "out";
       transfer.endpoint = 1;
       transfer.data = new ArrayBuffer(0);
       usb.bulkTransfer(device, transfer, function (result) {
         if (errorMessage) {
           chrome.test.assertLastError(errorMessage);
         } else {
           chrome.test.assertNoLastError();
         }
         chrome.test.assertTrue(resultCode == result.resultCode);
         chrome.test.succeed();
       });
     });
   };
 }
 
+function createIsochronousErrorTest(resultCode, errorMessage) {
+  return function() {
+    usb.findDevices({vendorId: 0, productId: 0}, function(devices) {
+      var device = devices[0];
+      var transfer = {
+        'transferInfo': {
+          'direction': "in",
+          'endpoint': 2,
+          'length': 160
+        },
+        'packets': 10,
+        'packetLength': 16
+      };
+      usb.isochronousTransfer(device, transfer, function (result) {
+        if (errorMessage) {
+          chrome.test.assertLastError(errorMessage);
+          // Device responds with only 8-byte packets and the second half fail.
+          chrome.test.assertTrue(result.data.byteLength == 40);
+        } else {
+          chrome.test.assertNoLastError();
+          // Device responds with a full set of 10 8-byte packets.
+          chrome.test.assertTrue(result.data.byteLength == 80);
+        }
+        chrome.test.assertTrue(resultCode == result.resultCode);
+        chrome.test.succeed();
+      });
+    });
+  };
+}
+
 var tests = [
   createErrorTest(0, undefined),
   createErrorTest(1, "Transfer failed."),
   createErrorTest(2, "Transfer timed out."),
+  createIsochronousErrorTest(0, undefined),
+  createIsochronousErrorTest(1, "Transfer failed."),
 ];
 
 chrome.test.runTests(tests);