Language settings: Fix Restart and Remove buttons shown at wrong times

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 106 matching lines @@
    * @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;
   },
 
   /**
    * @param {!LanguageState} languageState
    * @param {string} prospectiveUILanguage The chosen UI language.
-   * @return {boolean} True if the given language cannot be set/unset as the
+   * @return {boolean} True if the given language cannot be set as the
    *     prospective UI language by the user.
    * @private
    */
   disableUILanguageCheckbox_: function(languageState, prospectiveUILanguage) {
     // UI language setting belongs to the primary user.
     if (this.isSecondaryUser_())
       return true;
 
-    // If the language cannot be a UI language, we can't set/unset it as the
+    // If the language cannot be a UI language, we can't set it as the
     // prospective UI language.
     if (!languageState.language.supportsUI)
       return true;
 
-    // If the language already is the prospective UI language, it can't be unset
-    // if it is also the *actual* UI language, as we wouldn't know what other
-    // language to set as the prospective UI language.
-    if (languageState.language.code == navigator.language &&
-        (!prospectiveUILanguage ||
-         languageState.language.code == prospectiveUILanguage)) {
+    // Unchecking the currently chosen language doesn't make much sense.
+    if (languageState.language.code == prospectiveUILanguage)
       return true;
-    }
 
-    // Otherwise, the prospective language can be changed to/from this language.
+    // Otherwise, the prospective language can be changed to this language.
     return false;
   },
 
   /**
    * @return {boolean} True for a secondary user in a multi-profile session.
    * @private
    */
   isSecondaryUser_: function() {
     return cr.isChromeOS && loadTimeData.getBoolean('isSecondaryUser');
   },
 
   /**
    * Handler for changes to the UI language checkbox.
    * @param {!{target: !PaperCheckboxElement}} e
    * @private
    */
   onUILanguageChange_: function(e) {
-    if (e.target.checked) {
-      this.languageHelper.setUILanguage(this.detailLanguage_.language.code);
-    } else if (this.detailLanguage_.language.code ==
-        this.languageHelper.getProspectiveUILanguage()) {
-      // Reset the chosen UI language to the actual UI language.
-      this.languageHelper.resetUILanguage();
-    }
+    // We don't support unchecking this checkbox. TODO(michaelpg): Ask for a
+    // simpler widget.
+    assert(e.target.checked);
+    this.languageHelper.setProspectiveUILanguage(
+        this.detailLanguage_.language.code);
+
     /** @type {!CrActionMenuElement} */(this.$.menu.get()).close();
   },
 
    /**
    * @param {!chrome.languageSettingsPrivate.Language} language
    * @param {string} targetLanguageCode The default translate target language.
    * @return {boolean} True if the translate checkbox should be disabled.
    * @private
    */
   disableTranslateCheckbox_: function(language, targetLanguageCode) {
@@ skipping 164 matching lines @@
    * language to use in Chrome) matches the current language. This pref is used
    * only on Chrome OS and Windows; we don't control the UI language elsewhere.
    * @param {string} languageCode The language code identifying a language.
    * @param {string} prospectiveUILanguage The prospective UI language.
    * @return {boolean} True if the given language matches the prospective UI
    *     pref (which may be different from the actual UI language).
    * @private
    */
   isProspectiveUILanguage_: function(languageCode, prospectiveUILanguage) {
     assert(cr.isChromeOS || cr.isWindows);
-    return languageCode == this.languageHelper.getProspectiveUILanguage();
+    return languageCode == prospectiveUILanguage;
   },
 
 <if expr="chromeos or is_win">
    /**
+    * @param {string} prospectiveUILanguage
     * @return {string}
     * @private
     */
-  getProspectiveUILanguageName_: function() {
-    return this.languageHelper.getLanguage(
-        this.languageHelper.getProspectiveUILanguage()).displayName;
+  getProspectiveUILanguageName_: function(prospectiveUILanguage) {
+    return this.languageHelper.getLanguage(prospectiveUILanguage).displayName;
   },
 </if>
 
   /**
    * @return {string}
    * @private
    */
   getLanguageListTwoLine_: function() {
     return cr.isChromeOS || cr.isWindows ? 'two-line' : '';
   },
 
   /**
    * @return {string}
    * @private
    */
   getSpellCheckListTwoLine_: function() {
     return this.spellCheckSecondaryText_.length ? 'two-line' : '';
   },
 
   /**
    * Returns either the "selected" class, if the language matches the
    * prospective UI language, or an empty string. Languages can only be
    * selected on Chrome OS and Windows.
    * @param {string} languageCode The language code identifying a language.
    * @param {string} prospectiveUILanguage The prospective UI language.
-   * @param {boolean} supportsUI Whether Chrome's UI can be shown in this
-   *     language.
    * @return {string} The class name for the language item.
    * @private
    */
-  getLanguageItemClass_: function(languageCode, prospectiveUILanguage,
-      supportsUI) {
+  getLanguageItemClass_: function(languageCode, prospectiveUILanguage) {
     if ((cr.isChromeOS || cr.isWindows) &&
-        this.isProspectiveUILanguage_(languageCode, prospectiveUILanguage)) {
+        languageCode == prospectiveUILanguage) {
       return 'selected';
     }
     return '';
   },
 
    /**
    * @param {string} languageCode The language code identifying a language.
    * @param {string} prospectiveUILanguage The prospective UI language.
    * @return {boolean} True if the prospective UI language is set to
    *     |languageCode| but requires a restart to take effect.
    * @private
    */
   isRestartRequired_: function(languageCode, prospectiveUILanguage) {
     return prospectiveUILanguage == languageCode &&
-        navigator.language != languageCode;
+        this.languageHelper.requiresRestart();
   },
 
   /**
    * @param {string} id The input method ID.
    * @param {string} currentId The ID of the currently enabled input method.
    * @return {boolean} True if the IDs match.
    * @private
    */
   isCurrentInputMethod_: function(id, currentId) {
     assert(cr.isChromeOS);
@@ skipping 28 matching lines @@
    */
   forceRenderList_: function(tagName) {
     this.$$(tagName).$$('iron-list').fire('iron-resize');
   },
 
   /**
    * @param {!Event} e
    * @private
    */
   onDotsTap_: function(e) {
-    this.detailLanguage_ =
-        /** @type {!{model: !{item: !LanguageState}}} */(e).model.item;
+    // Set a copy of the LanguageState object since it is not data-bound to the
+    // languages model directly.
+    this.detailLanguage_ = /** @type {!LanguageState} */(Object.assign(
+        {},
+        /** @type {!{model: !{item: !LanguageState}}} */(e).model.item));
 
     // Ensure the template has been stamped.
     var menu = /** @type {?CrActionMenuElement} */(
         this.$.menu.getIfExists());
     if (!menu) {
       menu = /** @type {!CrActionMenuElement} */(this.$.menu.get());
       this.initializeMenu_(menu);
     }
 
     menu.showAt(/** @type {!Element} */ (e.target));
@@ skipping 43 matching lines @@
     if (e.target.tagName == expandButtonTag)
       return;
 
     /** @type {!CrExpandButtonElement} */
     var expandButton = e.currentTarget.querySelector(expandButtonTag);
     assert(expandButton);
     expandButton.expanded = !expandButton.expanded;
   },
 });
 })();