Add an automatic settings reset banner.

chrome/browser/resources/options/settings_banner.js

+// Copyright 2014 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('options', function() {
+
+  /**
+   * Base class for banners that appear at the top of the settings page.
+   */
+  function SettingsBannerBase() {}
+
+  cr.addSingletonGetter(SettingsBannerBase);
+
+  SettingsBannerBase.prototype = {
+    /**
+     * Whether or not the banner has already been dismissed.
+     *
+     * This is needed because of the surprising ordering of asynchronous
+     * JS<->native calls when the settings page is opened with specifying a
+     * given sub-page, e.g. chrome://settings/AutomaticSettingsReset.
+     *
+     * In such a case, AutomaticSettingsResetOverlay's didShowPage(), which
+     * calls our dismiss() method, would be called before the native Handlers'
+     * InitalizePage() methods have an effect in the JS, which includes calling
+     * our show() method. This would mean that the banner would be first
+     * dismissed, then shown. We want to prevent this.
+     *
+     * @type {boolean}
+     * @private
+     */
+    hadBeenDismissed_: false,
+
+    /**
+     * Metric name to send when a show event occurs.
+     */
+    showMetricName_: '',
+
+    /**
+     * Name of the native callback invoked when the banner is dismised.
+     */
+    dismissNativeCallbackName_: '',
+
+    /**
+     * DOM element whose visibility is set when setVisibility_ is called.
+     */
+    setVisibilibyDomElementSelector_: '',
+
+    /**
+     * Called by the native code to show the banner if needed.
+     * @private
+     */
+    show_: function() {
+      if (!this.hadBeenDismissed_) {
+        chrome.send('metricsHandler:recordAction', [this.showMetricName_]);
+        this.setVisibility_(true);
+      }
+    },
+
+    /**
+     * Called when the banner should be closed as a result of something taking
+     * place on the WebUI page, i.e. when its close button is pressed, or when
+     * the confirmation dialog for the profile settings reset feature is opened.
+     * @private
+     */
+    dismiss_: function() {
+      chrome.send(this.dismissNativeCallbackName_);
+      this.hadBeenDismissed_ = true;
+      this.setVisibility_(false);
+    },
+
+    /**
+     * Sets whether or not the reset profile settings banner shall be visible.
+     * @param {boolean} show Whether or not to show the banner.
+     * @private
+     */
+    setVisibility_: function(show) {
+      $(this.setVisibilibyDomElementSelector_).hidden = !show;

[Bernhard Bauer, 2014/02/08 17:38:46]

I think I'd slightly prefer passing in the actual DOM element instead of the
selector; it seems more dependency-injection-y :)

[robertshield, 2014/02/10 02:30:53]

Done.

+    },
+
+  };
+
+  // Export
+  return {
+    SettingsBannerBase: SettingsBannerBase
+  };
+});