Adds API test for imageWriterPrivate.writeFromFile

chrome/test/data/extensions/api_test/image_writer_private/list_devices/test.js

Index: chrome/test/data/extensions/api_test/image_writer_private/list_devices/test.js
diff --git a/chrome/test/data/extensions/api_test/image_writer_private/list_devices/test.js b/chrome/test/data/extensions/api_test/image_writer_private/list_devices/test.js
index 5643515dbb0378a280c486b85ed44485e4c8f3f1..03b75454fa48bb2c07247295e851255bd799190e 100644
--- a/chrome/test/data/extensions/api_test/image_writer_private/list_devices/test.js
+++ b/chrome/test/data/extensions/api_test/image_writer_private/list_devices/test.js
@@ -2,16 +2,17 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+
+// storage_unit_id is skipped because it is generated to point at a temporary
+// file.
 var expectedDevices = [{
   'vendor': 'Vendor 1',
   'model': 'Model 1',
-  'capacity': 1 << 20,
-  'storageUnitId': '/test/id/1',
+  'capacity': 1 << 15,
   }, {
   'vendor': 'Vendor 2',
   'model': 'Model 2',
-  'capacity': 1 << 22,
-  'storageUnitId': '/test/id/2',
+  'capacity': 1 << 17,
   }];
 
 
@@ -34,7 +35,6 @@ function listRemovableDevicesCallback(deviceList) {
     chrome.test.assertEq(expected.vendor, dev.vendor);
     chrome.test.assertEq(expected.model, dev.model);
     chrome.test.assertEq(expected.capacity, dev.capacity);
-    chrome.test.assertEq(expected.storageUnitId, dev.storageUnitId);
   });
 }