fix: navigator.languages to use OS preferred languages

atom/app/atom_main_delegate.h

@@ -35,6 +35,7 @@ class AtomMainDelegate : public content::ContentMainDelegate {
 #if defined(OS_MACOSX)
   bool ShouldSendMachPort(const std::string& process_type) override;
   bool DelaySandboxInitialization(const std::string& process_type) override;
+  std::string GetSystemPreferredLanguage();
 #endif
   bool ShouldLockSchemeRegistry() override;
   bool ShouldCreateFeatureList() override;

atom/app/atom_main_delegate_mac.mm

@@ -61,6 +61,11 @@
   base::mac::SetBaseBundleID(base_bundle_id.c_str());
 }
 
+std::string AtomMainDelegate::GetSystemPreferredLanguage() {
+  return base::SysNSStringToUTF8(
+      [[NSLocale preferredLanguages] objectAtIndex:0]);
+}
+
 void RegisterAtomCrApp() {
   // Force the NSApplication subclass to be used.
   [AtomApplication sharedApplication];

atom/browser/api/atom_api_web_contents.cc

@@ -405,7 +405,7 @@ void WebContents::InitWithSessionAndOptions(
   managed_web_contents()->GetView()->SetDelegate(this);
 
   auto* prefs = web_contents()->GetMutableRendererPrefs();
-  prefs->accept_languages = g_browser_process->GetApplicationLocale();
+  SetAcceptLanguages(prefs);
 
 #if defined(OS_LINUX) || defined(OS_WIN)
   // Update font settings.

atom/browser/api/atom_api_web_contents.h

@@ -35,6 +35,10 @@ namespace blink {
 struct WebDeviceEmulationParams;
 }
 
+namespace content {
+struct RendererPreferences;
+}
+
 namespace mate {
 class Arguments;
 class Dictionary;
@@ -514,6 +518,8 @@ class WebContents : public mate::TrackableObject<WebContents>,
 
   void InitZoomController(content::WebContents* web_contents,
                           const mate::Dictionary& options);
+  // Update the accept_languages pref
+  void SetAcceptLanguages(content::RendererPreferences* prefs);
 
   v8::Global<v8::Value> session_;
   v8::Global<v8::Value> devtools_web_contents_;

atom/browser/api/atom_api_web_contents_linux.cc

@@ -0,0 +1,20 @@
+// Copyright (c) 2019 GitHub, Inc.
+// Use of this source code is governed by the MIT license that can be
+// found in the LICENSE file.
+
+#include "atom/browser/api/atom_api_web_contents.h"
+
+#include "chrome/browser/browser_process.h"
+#include "content/public/common/renderer_preferences.h"
+
+namespace atom {
+
+namespace api {
+
+void WebContents::SetAcceptLanguages(content::RendererPreferences* prefs) {
+  prefs->accept_languages = g_browser_process->GetApplicationLocale();
+}
+
+}  // namespace api
+
+}  // namespace atom

atom/browser/api/atom_api_web_contents_mac.mm

@@ -3,7 +3,9 @@
 // found in the LICENSE file.
 
 #include "atom/browser/api/atom_api_web_contents.h"
+#include "base/strings/sys_string_conversions.h"
 #include "content/public/browser/render_widget_host_view.h"
+#include "content/public/common/renderer_preferences.h"
 
 #import <Cocoa/Cocoa.h>
 
@@ -27,6 +29,11 @@
   return view->HasFocus();
 }
 
+void WebContents::SetAcceptLanguages(content::RendererPreferences* prefs) {
+  prefs->accept_languages = base::SysNSStringToUTF8(
+      [[NSLocale preferredLanguages] componentsJoinedByString:@","]);
+}
+
 }  // namespace api
 
 }  // namespace atom

atom/browser/api/atom_api_web_contents_win.cc

@@ -0,0 +1,28 @@
+// Copyright (c) 2019 GitHub, Inc.
+// Use of this source code is governed by the MIT license that can be
+// found in the LICENSE file.
+
+#include "atom/browser/api/atom_api_web_contents.h"
+
+#include "base/strings/sys_string_conversions.h"
+#include "base/win/i18n.h"
+#include "content/public/common/renderer_preferences.h"
+
+namespace atom {
+
+namespace api {
+
+void WebContents::SetAcceptLanguages(content::RendererPreferences* prefs) {
+  std::vector<base::string16> languages;
+  base::win::i18n::GetThreadPreferredUILanguageList(&languages);
+  std::string accept_langs;
+  for (const auto& s16 : languages) {
+    accept_langs += base::SysWideToUTF8(s16) + ',';
+  }
+  accept_langs.pop_back();
+  prefs->accept_languages = accept_langs;
+}
+
+}  // namespace api
+
+}  // namespace atom

filenames.gni

@@ -188,6 +188,8 @@ filenames = {
     "atom/browser/api/atom_api_web_contents.h",
     "atom/browser/api/atom_api_web_contents_impl.cc",
     "atom/browser/api/atom_api_web_contents_mac.mm",
+    "atom/browser/api/atom_api_web_contents_linux.cc",
+    "atom/browser/api/atom_api_web_contents_win.cc",
     "atom/browser/api/atom_api_web_contents_view.cc",
     "atom/browser/api/atom_api_web_contents_view.h",
     "atom/browser/api/atom_api_web_request.cc",

spec/chromium-spec.js

@@ -200,10 +200,11 @@ describe('chromium feature', () => {
   })
 
   describe('navigator.languages', (done) => {
-    it('should return the system locale only', () => {
+    it('should return the system locales', () => {
       const appLocale = app.getLocale()
-      assert.strictEqual(navigator.languages.length, 1)
-      assert.strictEqual(navigator.languages[0], appLocale)
+      expect(navigator.languages.length).greaterThan(0)
+      // compare only the language not the region as appLocale provides that
+      expect(navigator.languages[0].split('-')[0]).equal(appLocale.split('-')[0])
     })
   })