Bug 1213450 - Complete the implementation of chrome.i18n - getAcceptLanguages, r=kmag

Implement browser.i18n.getAcceptLanguages() including tests
Rebase against fx-team, resolving some conflicts
Fix eslint errors/warnings

MozReview-Commit-ID: 52sZWsIHbl4

toolkit/components/extensions/ExtensionContent.jsm

@@ -120,6 +120,11 @@ var api = context => {
         return context.extension.localizeMessage(messageName, substitutions);
       },
 
+      getAcceptLanguages: function(callback) {
+        let result = context.extension.localeData.acceptLanguages;
+        return context.wrapPromise(Promise.resolve(result), callback);
+      },
+
       getUILanguage: function() {
         return context.extension.localeData.uiLocale;
       },

toolkit/components/extensions/ExtensionUtils.jsm

@@ -20,6 +20,8 @@ XPCOMUtils.defineLazyModuleGetter(this, "LanguageDetector",
                                   "resource:///modules/translation/LanguageDetector.jsm");
 XPCOMUtils.defineLazyModuleGetter(this, "Locale",
                                   "resource://gre/modules/Locale.jsm");
+XPCOMUtils.defineLazyModuleGetter(this, "Preferences",
+                                  "resource://gre/modules/Preferences.jsm");
 
 function filterStack(error) {
   return String(error.stack).replace(/(^.*(Task\.jsm|Promise-backend\.js).*\n)+/gm, "<Promise Chain>\n");
@@ -429,6 +431,16 @@ LocaleData.prototype = {
     return result;
   },
 
+  get acceptLanguages() {
+    let result = Preferences.get("intl.accept_languages", "", Ci.nsIPrefLocalizedString);
+    result = result.split(",");
+    result = result.map(lang => {
+      return lang.replace(/-/g, "_").trim();
+    });
+    return result;
+  },
+
+
   get uiLocale() {
     // Return the browser locale, but convert it to a Chrome-style
     // locale code.

toolkit/components/extensions/ext-i18n.js

@@ -12,6 +12,11 @@ extensions.registerSchemaAPI("i18n", null, (extension, context) => {
         return extension.localizeMessage(messageName, substitutions);
       },
 
+      getAcceptLanguages: function() {
+        let result = extension.localeData.acceptLanguages;
+        return Promise.resolve(result);
+      },
+
       getUILanguage: function() {
         return extension.localeData.uiLocale;
       },

toolkit/components/extensions/schemas/i18n.json

@@ -30,7 +30,6 @@
     "functions": [
       {
         "name": "getAcceptLanguages",
-        "unsupported": true,
         "type": "function",
         "description": "Gets the accept-languages of the browser. This is different from the locale used by the browser; to get the locale, use $(ref:i18n.getUILanguage).",
         "async": "callback",

toolkit/components/extensions/test/mochitest/test_ext_i18n.html

@@ -14,6 +14,7 @@
 <script type="text/javascript">
 "use strict";
 
+SimpleTest.registerCleanupFunction(() => { SpecialPowers.clearUserPref("intl.accept_languages"); });
 SimpleTest.registerCleanupFunction(() => { SpecialPowers.clearUserPref("general.useragent.locale"); });
 
 add_task(function* test_i18n() {
@@ -163,6 +164,85 @@ add_task(function* test_i18n() {
   yield extension.unload();
 });
 
+add_task(function* test_get_accept_languages() {
+  function background() {
+    function checkResults(source, results, expected) {
+      browser.test.assertEq(
+        expected.length,
+        results.length,
+        `got expected number of languages in ${source}`);
+      results.forEach((lang, index) => {
+        browser.test.assertEq(
+          expected[index],
+          lang,
+          `got expected language in ${source}`);
+      });
+    }
+
+    let tabId;
+
+    browser.tabs.query({currentWindow: true, active: true}, tabs => {
+      tabId = tabs[0].id;
+      browser.test.sendMessage("ready");
+    });
+
+    browser.test.onMessage.addListener(([msg, expected]) => {
+      Promise.all([
+        new Promise(
+          resolve => browser.tabs.sendMessage(tabId, "get-results", resolve)),
+        browser.i18n.getAcceptLanguages(),
+      ]).then(([contentResults, backgroundResults]) => {
+        checkResults("contentScript", contentResults, expected);
+        checkResults("background", backgroundResults, expected);
+
+        browser.test.sendMessage("done");
+      });
+    });
+  }
+
+  function content() {
+    browser.runtime.onMessage.addListener((msg, sender, respond) => {
+      browser.i18n.getAcceptLanguages(respond);
+      return true;
+    });
+  }
+
+  let extension = ExtensionTestUtils.loadExtension({
+    manifest: {
+      "content_scripts": [{
+        "matches": ["http://mochi.test/*/file_sample.html"],
+        "run_at": "document_start",
+        "js": ["content_script.js"],
+      }],
+    },
+
+    background: `(${background})()`,
+
+    files: {
+      "content_script.js": `(${content})()`,
+    },
+  });
+
+  let win = window.open("file_sample.html");
+
+  yield extension.startup();
+  yield extension.awaitMessage("ready");
+
+  let expectedLangs = ["en_US", "en"];
+  extension.sendMessage(["expect-results", expectedLangs]);
+  yield extension.awaitMessage("done");
+
+  expectedLangs = ["en_US", "en", "fr_CA", "fr"];
+  SpecialPowers.setCharPref("intl.accept_languages", expectedLangs.toString());
+  extension.sendMessage(["expect-results", expectedLangs]);
+  yield extension.awaitMessage("done");
+  SpecialPowers.clearUserPref("intl.accept_languages");
+
+  win.close();
+
+  yield extension.unload();
+});
+
 add_task(function* test_get_ui_language() {
   function getResults() {
     return {