Add sample extension that allows setting plugin-specific content settings.

chrome/common/extensions/docs/examples/extensions/plugin_settings/domui/js/cr/ui/list_item.js

Index: chrome/common/extensions/docs/examples/extensions/plugin_settings/domui/js/cr/ui/list_item.js
diff --git a/chrome/common/extensions/docs/examples/extensions/plugin_settings/domui/js/cr/ui/list_item.js b/chrome/common/extensions/docs/examples/extensions/plugin_settings/domui/js/cr/ui/list_item.js
new file mode 100644
index 0000000000000000000000000000000000000000..68431bc0d9f2e4288bdfca07b61c3261db150d45
--- /dev/null
+++ b/chrome/common/extensions/docs/examples/extensions/plugin_settings/domui/js/cr/ui/list_item.js
@@ -0,0 +1,75 @@
+// Copyright (c) 2011 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.
+
+cr.define('cr.ui', function() {
+
+  /**
+   * Creates a new list item element.
+   * @param {string} opt_label The text label for the item.
+   * @constructor
+   * @extends {HTMLLIElement}
+   */
+  var ListItem = cr.ui.define('li');
+
+  ListItem.prototype = {
+    __proto__: HTMLLIElement.prototype,
+
+    /**
+     * Plain text label.
+     * @type {string}
+     */
+    get label() {
+      return this.textContent;
+    },
+    set label(label) {
+      this.textContent = label;
+    },
+
+    /**
+     * This item's index in the containing list.
+     * @type {number}
+     */
+    listIndex_: -1,
+
+    /**
+     * Called when an element is decorated as a list item.
+     */
+    decorate: function() {
+      this.setAttribute('role', 'listitem');
+    },
+
+    /**
+     * Called when the selection state of this element changes.
+     */
+    selectionChanged: function() {
+    },
+  };
+
+  /**
+   * Whether the item is selected. Setting this does not update the underlying
+   * selection model. This is only used for display purpose.
+   * @type {boolean}
+   */
+  cr.defineProperty(ListItem, 'selected', cr.PropertyKind.BOOL_ATTR,
+                    function() {
+                      this.selectionChanged();
+                    });
+
+  /**
+   * Whether the item is the lead in a selection. Setting this does not update
+   * the underlying selection model. This is only used for display purpose.
+   * @type {boolean}
+   */
+  cr.defineProperty(ListItem, 'lead', cr.PropertyKind.BOOL_ATTR);
+
+  /**
+   * This item's index in the containing list.
+   * @type {number}
+   */
+  cr.defineProperty(ListItem, 'listIndex');
+
+  return {
+    ListItem: ListItem
+  };
+});