Fix test failure in list_selection_model_test.html and port to automated browser test.

ui/webui/resources/js/cr/ui/list_selection_model_test_util.js

Index: ui/webui/resources/js/cr/ui/list_selection_model_test_util.js
diff --git a/ui/webui/resources/js/cr/ui/list_selection_model_test_util.js b/ui/webui/resources/js/cr/ui/list_selection_model_test_util.js
deleted file mode 100644
index 46b1ba7b990916898af6f777fb574f23e410b862..0000000000000000000000000000000000000000
--- a/ui/webui/resources/js/cr/ui/list_selection_model_test_util.js
+++ /dev/null
@@ -1,26 +0,0 @@
-// 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.
-
-function range(start, end) {
-  var a = [];
-  for (var i = start; i <= end; i++) {
-    a.push(i);
-  }
-  return a;
-}
-
-function adjust(sm, index, removed, added) {
-  var permutation = [];
-  for (var i = 0; i < index; i++) {
-    permutation.push(i);
-  }
-  for (var i = 0; i < removed; i++) {
-    permutation.push(-1);
-  }
-  for (var i = index + removed; i < sm.length; i++) {
-    permutation.push(i - removed + added);
-  }
-  sm.adjustLength(sm.length - removed + added);
-  sm.adjustToReordering(permutation);
-}