MD Settings: Allow the user to order the list of languages.

chrome/browser/resources/settings/languages_page/languages_page.js

 // Copyright 2015 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.
 
 /**
  * @fileoverview 'settings-languages-page' is the settings page
  * for language and input method settings.
  */
 (function() {
 'use strict';
@@ skipping 53 matching lines @@
   /**
    * Handler for clicking a language on the main page, which selects the
    * language as the prospective UI language on Chrome OS and Windows.
    * @param {!{model: !{item: !LanguageState}}} e
    */
   onLanguageTap_: function(e) {
     // Only change the UI language on platforms that allow it.
     if (!cr.isChromeOS && !cr.isWindows)
       return;
 
-    // Taps on the paper-icon-button are handled in onShowLanguageDetailTap_.
-    if (e.target.tagName == 'PAPER-ICON-BUTTON')
-      return;
-
     // Set the prospective UI language. This won't take effect until a restart.
     if (e.model.item.language.supportsUI)
       this.languageHelper_.setUILanguage(e.model.item.language.code);
   },
 
   /**
    * Handler for enabling or disabling spell check.
    * @param {!{target: Element, model: !{item: !LanguageState}}} e
    */
   onSpellCheckChange_: function(e) {
     this.languageHelper_.toggleSpellCheck(e.model.item.language.code,
                                           e.target.checked);
   },
 
   /** @private */
   onBackTap_: function() {
     this.$.pages.back();
   },
 
   /**
    * Opens the Manage Languages page.
    * @private
    */
   onManageLanguagesTap_: function() {
     this.$.pages.setSubpageChain(['manage-languages']);
     this.forceRenderList_('settings-manage-languages-page');
   },
 
   /**
+   * @param {number} index Index of the language in the list of languages.
+   * @param {!Object} change Polymer change object for languages.enabled.*.
+   * @return {boolean} True if the given language is the first one in the list
+   *     of languages.
+   * @private
+   */
+  isFirstLanguage_: function(index, change) {
+    return index == 0;
+  },
+
+  /**
+   * @param {number} index Index of the language in the list of languages.
+   * @param {!Object} change Polymer change object for languages.enabled.*.
+   * @return {boolean} True if the given language is the last one in the list of
+   *     languages.
+   * @private
+   */
+  isLastLanguage_: function(index, change) {
+    return index == this.languages.enabled.length - 1;
+  },
+
+  /**
+   * @param {!Object} change Polymer change object for languages.enabled.*.
+   * @return {boolean} True if there are less than 2 languages.
+   */
+  isHelpTextHidden_: function(change) {
+    return this.languages.enabled.length <= 1;
+  },
+
+  /**
+   * Moves the language up in the list.
+   * @param {!{model: !{item: !LanguageState}}} e
+   * @private
+   */
+  onMoveUpTap_: function(e) {
+    this.languageHelper_.moveLanguage(e.model.item.language.code, -1);
+  },
+
+  /**
+   * Moves the language down in the list.
+   * @param {!{model: !{item: !LanguageState}}} e
+   * @private
+   */
+  onMoveDownTap_: function(e) {
+    this.languageHelper_.moveLanguage(e.model.item.language.code, 1);
+  },
+
+  /**
    * Opens the Language Detail page for the language.
    * @param {!{model: !{item: !LanguageState}}} e
    * @private
    */
   onShowLanguageDetailTap_: function(e) {
     this.detailLanguage_ = e.model.item;
     this.$.pages.setSubpageChain(['language-detail']);
   },
 
   /**
@@ skipping 157 matching lines @@
    * HACK(michaelpg): This is necessary to show the list when navigating to
    * the sub-page. Remove this function when PolymerElements/neon-animation#60
    * is fixed.
    * @param {string} tagName Name of the element containing the <iron-list>.
    */
   forceRenderList_: function(tagName) {
     this.$$(tagName).$$('iron-list').fire('iron-resize');
   },
 });
 })();