refactor: Move OS utility to language_util

filenames.gni

@@ -109,11 +109,9 @@ filenames = {
     "shell/browser/api/electron_api_web_contents.cc",
     "shell/browser/api/electron_api_web_contents.h",
     "shell/browser/api/electron_api_web_contents_impl.cc",
-    "shell/browser/api/electron_api_web_contents_linux.cc",
     "shell/browser/api/electron_api_web_contents_mac.mm",
     "shell/browser/api/electron_api_web_contents_view.cc",
     "shell/browser/api/electron_api_web_contents_view.h",
-    "shell/browser/api/electron_api_web_contents_win.cc",
     "shell/browser/api/electron_api_web_request.cc",
     "shell/browser/api/electron_api_web_request.h",
     "shell/browser/api/electron_api_web_view_manager.cc",
@@ -547,6 +545,10 @@ filenames = {
     "shell/common/key_weak_map.h",
     "shell/common/keyboard_util.cc",
     "shell/common/keyboard_util.h",
+    "shell/common/language_util.h",
+    "shell/common/language_util_linux.cc",
+    "shell/common/language_util_mac.mm",
+    "shell/common/language_util_win.cc",
     "shell/common/mac/main_application_bundle.h",
     "shell/common/mac/main_application_bundle.mm",
     "shell/common/mouse_util.cc",

shell/browser/api/electron_api_web_contents.cc

@@ -89,6 +89,7 @@
 #include "shell/common/gin_converters/value_converter.h"
 #include "shell/common/gin_helper/dictionary.h"
 #include "shell/common/gin_helper/object_template_builder.h"
+#include "shell/common/language_util.h"
 #include "shell/common/mouse_util.h"
 #include "shell/common/node_includes.h"
 #include "shell/common/options_switches.h"
@@ -102,6 +103,7 @@
 #include "third_party/blink/public/mojom/messaging/transferable_message.mojom.h"
 #include "third_party/blink/public/mojom/renderer_preferences.mojom.h"
 #include "ui/base/cursor/cursor.h"
+#include "ui/base/l10n/l10n_util.h"
 #include "ui/base/mojom/cursor_type.mojom-shared.h"
 #include "ui/display/screen.h"
 #include "ui/events/base_event_utils.h"
@@ -535,7 +537,22 @@ void WebContents::InitWithSessionAndOptions(
   managed_web_contents()->GetView()->SetDelegate(this);
 
   auto* prefs = web_contents()->GetMutableRendererPrefs();
-  SetAcceptLanguages(prefs);
+
+  // Collect preferred languages from OS and browser process. accept_languages
+  // affects HTTP header, navigator.languages, and CJK fallback font seleciton.
+  //
+  // Note that an application locale set to the browser process might be
+  // different with the one set to the preference list.
+  // (e.g. overridden with --lang)
+  std::string accept_languages =
+      g_browser_process->GetApplicationLocale() + ",";
+  for (auto const& language : electron::GetPreferredLanguages()) {
+    if (language == g_browser_process->GetApplicationLocale())
+      continue;
+    accept_languages += language + ",";
+  }
+  accept_languages.pop_back();
+  prefs->accept_languages = accept_languages;
 
 #if defined(OS_LINUX) || defined(OS_WIN)
   // Update font settings.

shell/browser/api/electron_api_web_contents.h

@@ -579,12 +579,6 @@ class WebContents : public gin_helper::TrackableObject<WebContents>,
   void InitZoomController(content::WebContents* web_contents,
                           const gin_helper::Dictionary& options);
 
-  void SetAcceptLanguages(blink::mojom::RendererPreferences* prefs);
-#if defined(OS_WIN)
-  // Get OS preferred languages in Windows 10 or later
-  bool GetLanguagesUsingGlobalization(std::vector<base::string16>* languages);
-#endif
-
   v8::Global<v8::Value> session_;
   v8::Global<v8::Value> devtools_web_contents_;
   v8::Global<v8::Value> debugger_;

shell/browser/api/electron_api_web_contents_mac.mm

@@ -29,11 +29,6 @@
   return view->HasFocus();
 }
 
-void WebContents::SetAcceptLanguages(blink::mojom::RendererPreferences* prefs) {
-  prefs->accept_languages = base::SysNSStringToUTF8(
-      [[NSLocale preferredLanguages] componentsJoinedByString:@","]);
-}
-
 }  // namespace api
 
 }  // namespace electron

shell/common/language_util.h

@@ -0,0 +1,26 @@
+// Copyright (c) 2020 GitHub, Inc.
+// Use of this source code is governed by the MIT license that can be
+// found in the LICENSE file.
+
+#ifndef SHELL_COMMON_LANGUAGE_UTIL_H_
+#define SHELL_COMMON_LANGUAGE_UTIL_H_
+
+#include <string>
+#include <vector>
+
+#include "base/strings/string16.h"
+
+namespace electron {
+
+// Return a list of user preferred languages from OS. The list doesn't include
+// overrides from command line arguments.
+std::vector<std::string> GetPreferredLanguages();
+
+#if defined(OS_WIN)
+bool GetPreferredLanguagesUsingGlobalization(
+    std::vector<base::string16>* languages);
+#endif
+
+}  // namespace electron
+
+#endif  // SHELL_COMMON_LANGUAGE_UTIL_H_

shell/common/language_util_linux.cc

@@ -0,0 +1,16 @@
+// Copyright (c) 2020 GitHub, Inc.
+// Use of this source code is governed by the MIT license that can be
+// found in the LICENSE file.
+
+#include "shell/common/language_util.h"
+
+#include "ui/base/l10n/l10n_util.h"
+
+namespace electron {
+
+std::vector<std::string> GetPreferredLanguages() {
+  std::vector<std::string> languages = {l10n_util::GetApplicationLocale("")};
+  return languages;
+}
+
+}  // namespace electron

shell/common/language_util_mac.mm

@@ -0,0 +1,23 @@
+// Copyright (c) 2020 GitHub, Inc.
+// Use of this source code is governed by the MIT license that can be
+// found in the LICENSE file.
+
+#include "shell/common/language_util.h"
+
+#import <Cocoa/Cocoa.h>
+
+#include "base/strings/sys_string_conversions.h"
+
+namespace electron {
+
+std::vector<std::string> GetPreferredLanguages() {
+  std::vector<std::string> languages;
+  [[NSLocale preferredLanguages]
+      enumerateObjectsUsingBlock:^(NSString* language, NSUInteger i,
+                                   BOOL* stop) {
+        languages.push_back(base::SysNSStringToUTF8(language));
+      }];
+  return languages;
+}
+
+}  // namespace electron

shell/browser/api/electron_api_web_contents_win.cc → shell/common/language_util_win.cc

@@ -2,7 +2,7 @@
 // Use of this source code is governed by the MIT license that can be
 // found in the LICENSE file.
 
-#include "shell/browser/api/electron_api_web_contents.h"
+#include "shell/common/language_util.h"
 
 #include <roapi.h>
 #include <windows.system.userprofile.h>
@@ -13,30 +13,26 @@
 #include "base/win/i18n.h"
 #include "base/win/win_util.h"
 #include "base/win/windows_version.h"
-#include "third_party/blink/public/mojom/renderer_preferences.mojom.h"
 
 namespace electron {
 
-namespace api {
-
-void WebContents::SetAcceptLanguages(blink::mojom::RendererPreferences* prefs) {
-  std::vector<base::string16> languages;
+std::vector<std::string> GetPreferredLanguages() {
+  std::vector<base::string16> languages16;
 
   // Attempt to use API available on Windows 10 or later, which
   // returns the full list of language preferences.
-  if (!GetLanguagesUsingGlobalization(&languages)) {
-    base::win::i18n::GetThreadPreferredUILanguageList(&languages);
+  if (!GetPreferredLanguagesUsingGlobalization(&languages16)) {
+    base::win::i18n::GetThreadPreferredUILanguageList(&languages16);
   }
 
-  std::string accept_langs;
-  for (const auto& language : languages) {
-    accept_langs += base::SysWideToUTF8(language) + ',';
+  std::vector<std::string> languages;
+  for (const auto& language : languages16) {
+    languages.push_back(base::SysWideToUTF8(language));
   }
-  accept_langs.pop_back();
-  prefs->accept_languages = accept_langs;
+  return languages;
 }
 
-bool WebContents::GetLanguagesUsingGlobalization(
+bool GetPreferredLanguagesUsingGlobalization(
     std::vector<base::string16>* languages) {
   if (base::win::GetVersion() < base::win::Version::WIN10)
     return false;
@@ -77,6 +73,4 @@ bool WebContents::GetLanguagesUsingGlobalization(
   return true;
 }
 
-}  // namespace api
-
 }  // namespace electron