Bug 1857002 - Move getLanguageList from browser to toolkit r=gregtatum,settings-reviewers,mconley

This function is helpful for GeckoView and Translations on Android.
Moving it to toolkit for shared use.

Differential Revision: https://phabricator.services.mozilla.com/D190118

browser/components/preferences/main.js

@@ -1049,7 +1049,7 @@ var gMainPane = {
         const supportedLanguages =
           await TranslationsParent.getSupportedLanguages();
         const languageList =
-          TranslationsState.getLanguageList(supportedLanguages);
+          TranslationsParent.getLanguageList(supportedLanguages);
         const downloadPhases = await TranslationsState.createDownloadPhases(
           languageList
         );
@@ -1067,38 +1067,6 @@ var gMainPane = {
         );
       }
 
-      /**
-       * Create a unique list of languages, sorted by the display name.
-       *
-       * @param {Object} supportedLanguages
-       * @returns {Array<{ langTag: string, displayName: string}}
-       */
-      static getLanguageList(supportedLanguages) {
-        const displayNames = new Map();
-        for (const languages of [
-          supportedLanguages.fromLanguages,
-          supportedLanguages.toLanguages,
-        ]) {
-          for (const { langTag, displayName } of languages) {
-            displayNames.set(langTag, displayName);
-          }
-        }
-
-        let appLangTag = new Intl.Locale(Services.locale.appLocaleAsBCP47)
-          .language;
-
-        // Don't offer to download the app's language.
-        displayNames.delete(appLangTag);
-
-        // Sort the list of languages by the display names.
-        return [...displayNames.entries()]
-          .map(([langTag, displayName]) => ({
-            langTag,
-            displayName,
-          }))
-          .sort((a, b) => a.displayName.localeCompare(b.displayName));
-      }
-
       /**
        * Determine the download phase of each language file.
        *

toolkit/components/translations/actors/TranslationsParent.sys.mjs

@@ -1088,6 +1088,37 @@ export class TranslationsParent extends JSWindowActorParent {
     };
   }
 
+  /**
+   * Create a unique list of languages, sorted by the display name.
+   *
+   * @param {Object} supportedLanguages
+   * @returns {Array<{ langTag: string, displayName: string}}
+   */
+  static getLanguageList(supportedLanguages) {
+    const displayNames = new Map();
+    for (const languages of [
+      supportedLanguages.fromLanguages,
+      supportedLanguages.toLanguages,
+    ]) {
+      for (const { langTag, displayName } of languages) {
+        displayNames.set(langTag, displayName);
+      }
+    }
+
+    let appLangTag = new Intl.Locale(Services.locale.appLocaleAsBCP47).language;
+
+    // Don't offer to download the app's language.
+    displayNames.delete(appLangTag);
+
+    // Sort the list of languages by the display names.
+    return [...displayNames.entries()]
+      .map(([langTag, displayName]) => ({
+        langTag,
+        displayName,
+      }))
+      .sort((a, b) => a.displayName.localeCompare(b.displayName));
+  }
+
   /**
    * @param {Object} event
    * @param {Object} event.data