MD Settings: Enable to search "Add languages" list.

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

Index: chrome/browser/resources/settings/languages_page/add_languages_dialog.js
diff --git a/chrome/browser/resources/settings/languages_page/add_languages_dialog.js b/chrome/browser/resources/settings/languages_page/add_languages_dialog.js
index 8c687d7ea027f571ad410bdfa8a7aba418bd0a1d..1dffd25b80f71f6ce52555f9b09fbaf877b40883 100644
--- a/chrome/browser/resources/settings/languages_page/add_languages_dialog.js
+++ b/chrome/browser/resources/settings/languages_page/add_languages_dialog.js
@@ -30,6 +30,12 @@ Polymer({
       type: Boolean,
       value: true,
     },
+
+    /** @private */
+    filterValue_: {
+      type: String,
+      value: '',
+    },
   },
 
   attached: function() {
@@ -55,18 +61,31 @@ Polymer({
   },
 
   /**
-   * Returns the supported languages that are not yet enabled, based on
+   * Returns the supported languages that are not yet enabled
+   * and matching with filter keyword, based on
    * the LanguageHelper's enabled languages list.
    * @param {!Array<!chrome.languageSettingsPrivate.Language>}
    *     supportedLanguages
    * @param {!Object} enabledLanguagesChange Polymer change record for
    *     |enabledLanguages|.
+   * @param {string} filterValue Keyword to filter languages in
+   *     supported languages.
    * @return {!Array<!chrome.languageSettingsPrivate.Language>}
    * @private
    */
-  getAvailableLanguages_: function(supportedLanguages, enabledLanguagesChange) {
+  getAvailableLanguages_: function(supportedLanguages,
+                                   enabledLanguagesChange,
+                                   filterValue) {
     return supportedLanguages.filter(function(language) {
-      return !this.languageHelper.isLanguageEnabled(language.code);
+      var isAvailableLanguage =
+          !this.languageHelper.isLanguageEnabled(language.code);
+      if (!filterValue) {
+        return isAvailableLanguage;
+      } else {
+        return isAvailableLanguage &&
+          language.displayName
+                  .toLowerCase().includes(filterValue.toLowerCase());
+      }
     }.bind(this));
   },