MD Settings: reduce complexity and overhead of Languages singleton

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

Index: chrome/browser/resources/settings/languages_page/manage_languages_page.js
diff --git a/chrome/browser/resources/settings/languages_page/manage_languages_page.js b/chrome/browser/resources/settings/languages_page/manage_languages_page.js
index 2de5a18198b5f0cc2b192d58723051ff3451ee13..f94232d69580fe56086e2597572991b013c3d0a3 100644
--- a/chrome/browser/resources/settings/languages_page/manage_languages_page.js
+++ b/chrome/browser/resources/settings/languages_page/manage_languages_page.js
@@ -25,14 +25,6 @@ Polymer({
       type: Object,
       notify: true,
     },
-
-    /** @private {!LanguageHelper} */
-    languageHelper_: Object,
-  },
-
-  /** @override */
-  created: function() {
-     this.languageHelper_ = LanguageHelperImpl.getInstance();
   },
 
   /**
@@ -43,12 +35,14 @@ Polymer({
    * @private
    */
   isCheckboxChecked_: function(language, change) {
-    return this.languageHelper_.isLanguageEnabled(language.code);
+    return settings.LanguageHelperImpl.getInstance().isLanguageEnabled(
+        language.code);
   },
 
   /**
    * Determines whether a language must be enabled. If so, the checkbox in the
-   * available languages list should not be changeable.
+   * available languages list should not be changeable. Only applies to
+   * already-enabled languages.
    * @param {!chrome.languageSettingsPrivate.Language} language
    * @param {!Object} change Polymer change object (provided in the HTML so this
    *     gets called whenever languages.enabled.* changes).
@@ -56,10 +50,9 @@ Polymer({
    * @private
    */
   isLanguageRequired_: function(language, change) {
-    // This check only applies to enabled languages.
-    if (!this.languageHelper_.isLanguageEnabled(language.code))
-      return false;
-    return !this.languageHelper_.canDisableLanguage(language.code);
+    var languageHelper = settings.LanguageHelperImpl.getInstance();
+    return languageHelper.isLanguageEnabled(language.code) &&
+        !languageHelper.canDisableLanguage(language.code);
   },
 
   /**
@@ -68,7 +61,8 @@ Polymer({
    * @private
    */
   onRemoveLanguageTap_: function(e) {
-    this.languageHelper_.disableLanguage(e.model.item.language.code);
+    settings.LanguageHelperImpl.getInstance().disableLanguage(
+        e.model.item.language.code);
   },
 
   /**
@@ -80,8 +74,8 @@ Polymer({
   onLanguageCheckboxChange_: function(e) {
     var code = e.model.item.code;
     if (e.target.checked)
-      this.languageHelper_.enableLanguage(code);
+      settings.LanguageHelperImpl.getInstance().enableLanguage(code);
     else
-      this.languageHelper_.disableLanguage(code);
+      settings.LanguageHelperImpl.getInstance().disableLanguage(code);
   },
 });