chrome: Support configuration of accept language (see issue #2969)

This change adds support for CEF settings configuration of accept_language_list.
If specified, this value will take precedence over the "intl.accept_languages"
preference which is controlled by chrome://settings/languages.

libcef/browser/chrome/chrome_browser_context.cc

@@ -4,7 +4,6 @@
 
 #include "libcef/browser/chrome/chrome_browser_context.h"
 
-#include "libcef/browser/prefs/browser_prefs.h"
 #include "libcef/browser/thread_util.h"
 
 #include "chrome/browser/browser_process.h"
@@ -110,7 +109,6 @@ void ChromeBrowserContext::ProfileCreated(Profile* profile,
 
   if (status == Profile::CreateStatus::CREATE_STATUS_INITIALIZED) {
     CHECK(profile_);
-    browser_prefs::SetLanguagePrefs(profile_);
 
     // Must set |profile_| before Init() calls
     // ChromeContentBrowserClientCef::ConfigureNetworkContextParams so that

libcef/browser/chrome/chrome_content_browser_client_cef.cc

@@ -16,6 +16,7 @@
 #include "libcef/browser/net_service/login_delegate.h"
 #include "libcef/browser/net_service/proxy_url_loader_factory.h"
 #include "libcef/browser/net_service/resource_request_handler_wrapper.h"
+#include "libcef/browser/prefs/browser_prefs.h"
 #include "libcef/browser/prefs/renderer_prefs.h"
 #include "libcef/common/app_manager.h"
 #include "libcef/common/cef_switches.h"
@@ -307,6 +308,17 @@ void ChromeContentBrowserClientCef::ConfigureNetworkContextParams(
   network_context_params->cookieable_schemes =
       cef_context ? cef_context->GetCookieableSchemes()
                   : CefBrowserContext::GetGlobalCookieableSchemes();
+
+  // Prefer the CEF settings configuration, if specified, instead of the
+  // kAcceptLanguages preference which is controlled by the
+  // chrome://settings/languages configuration.
+  const std::string& accept_language_list =
+      browser_prefs::GetAcceptLanguageList(cef_context, /*browser=*/nullptr,
+                                           /*expand=*/true);
+  if (!accept_language_list.empty() &&
+      accept_language_list != network_context_params->accept_language) {
+    network_context_params->accept_language = accept_language_list;
+  }
 }
 
 std::unique_ptr<content::LoginDelegate>

libcef/browser/context.cc

@@ -435,8 +435,6 @@ void CefContext::PopulateGlobalRequestContextSettings(
   settings->ignore_certificate_errors =
       settings_.ignore_certificate_errors ||
       command_line->HasSwitch(switches::kIgnoreCertificateErrors);
-  CefString(&settings->accept_language_list) =
-      CefString(&settings_.accept_language_list);
 
   CefString(&settings->cookieable_schemes_list) =
       CefString(&settings_.cookieable_schemes_list);
@@ -449,12 +447,6 @@ void CefContext::NormalizeRequestContextSettings(
   // The |root_cache_path| value was already normalized in Initialize.
   const base::FilePath& root_cache_path = CefString(&settings_.root_cache_path);
   NormalizeCachePathAndSet(settings->cache_path, root_cache_path);
-
-  if (settings->accept_language_list.length == 0) {
-    // Use the global language list setting.
-    CefString(&settings->accept_language_list) =
-        CefString(&settings_.accept_language_list);
-  }
 }
 
 void CefContext::AddObserver(Observer* observer) {

libcef/browser/net_service/resource_request_handler_wrapper.cc

@@ -11,6 +11,7 @@
 #include "libcef/browser/net_service/proxy_url_loader_factory.h"
 #include "libcef/browser/net_service/resource_handler_wrapper.h"
 #include "libcef/browser/net_service/response_filter_wrapper.h"
+#include "libcef/browser/prefs/browser_prefs.h"
 #include "libcef/browser/thread_util.h"
 #include "libcef/common/app_manager.h"
 #include "libcef/common/net/scheme_registration.h"
@@ -28,7 +29,6 @@
 #include "content/public/browser/web_contents.h"
 #include "net/base/load_flags.h"
 #include "net/http/http_status_code.h"
-#include "net/http/http_util.h"
 #include "third_party/blink/public/mojom/loader/resource_load_info.mojom-shared.h"
 #include "ui/base/page_transition_types.h"
 #include "url/origin.h"
@@ -78,28 +78,6 @@ class RequestCallbackWrapper : public CefRequestCallback {
   DISALLOW_COPY_AND_ASSIGN(RequestCallbackWrapper);
 };
 
-std::string GetAcceptLanguageList(content::BrowserContext* browser_context,
-                                  CefRefPtr<CefBrowserHostBase> browser) {
-  if (browser) {
-    const CefBrowserSettings& browser_settings = browser->settings();
-    if (browser_settings.accept_language_list.length > 0) {
-      return CefString(&browser_settings.accept_language_list);
-    }
-  }
-
-  // This defaults to the value from CefRequestContextSettings via
-  // browser_prefs::CreatePrefService().
-  auto prefs = Profile::FromBrowserContext(browser_context)->GetPrefs();
-  return prefs->GetString(language::prefs::kAcceptLanguages);
-}
-
-// Match the logic in chrome/browser/net/profile_network_context_service.cc.
-std::string ComputeAcceptLanguageFromPref(const std::string& language_pref) {
-  std::string accept_languages_str =
-      net::HttpUtil::ExpandLanguageList(language_pref);
-  return net::HttpUtil::GenerateAcceptLanguageHeader(accept_languages_str);
-}
-
 class InterceptedRequestHandlerWrapper : public InterceptedRequestHandler {
  public:
   struct RequestState {
@@ -286,8 +264,8 @@ class InterceptedRequestHandlerWrapper : public InterceptedRequestHandler {
       unhandled_request_callback_ = unhandled_request_callback;
 
       // Default values for standard headers.
-      accept_language_ = ComputeAcceptLanguageFromPref(
-          GetAcceptLanguageList(browser_context, browser));
+      accept_language_ = browser_prefs::GetAcceptLanguageList(
+          cef_browser_context, browser.get(), /*expand=*/true);
       DCHECK(!accept_language_.empty());
       user_agent_ =
           CefAppManager::Get()->GetContentClient()->browser()->GetUserAgent();

libcef/browser/prefs/browser_prefs.cc

@@ -5,6 +5,8 @@
 #include "libcef/browser/prefs/browser_prefs.h"
 
 #include "libcef/browser/browser_context.h"
+#include "libcef/browser/browser_host_base.h"
+#include "libcef/browser/context.h"
 #include "libcef/browser/media_capture_devices_dispatcher.h"
 #include "libcef/browser/prefs/pref_store.h"
 #include "libcef/browser/prefs/renderer_prefs.h"
@@ -58,6 +60,7 @@
 #include "content/public/browser/browser_thread.h"
 #include "extensions/browser/extension_prefs.h"
 #include "extensions/buildflags/buildflags.h"
+#include "net/http/http_util.h"
 #include "ui/base/l10n/l10n_util.h"
 #include "ui/base/ui_base_switches.h"
 
@@ -75,12 +78,35 @@ namespace browser_prefs {
 
 namespace {
 
-std::string GetAcceptLanguageList(Profile* profile) {
-  const CefRequestContextSettings& context_settings =
-      CefBrowserContext::FromBrowserContext(profile)->settings();
-  if (context_settings.accept_language_list.length > 0) {
-    return CefString(&context_settings.accept_language_list);
+// Match the logic in chrome/browser/net/profile_network_context_service.cc.
+std::string ComputeAcceptLanguageFromPref(const std::string& language_pref) {
+  std::string accept_languages_str =
+      net::HttpUtil::ExpandLanguageList(language_pref);
+  return net::HttpUtil::GenerateAcceptLanguageHeader(accept_languages_str);
+}
+
+// Return the most relevant setting based on |browser_context| and |browser|.
+std::string GetAcceptLanguageListSetting(CefBrowserContext* browser_context,
+                                         CefBrowserHostBase* browser) {
+  if (browser) {
+    const auto& settings = browser->settings();
+    if (settings.accept_language_list.length > 0) {
+      return CefString(&settings.accept_language_list);
+    }
   }
+
+  if (browser_context) {
+    const auto& settings = browser_context->settings();
+    if (settings.accept_language_list.length > 0) {
+      return CefString(&settings.accept_language_list);
+    }
+  }
+
+  const auto& settings = CefContext::Get()->settings();
+  if (settings.accept_language_list.length > 0) {
+    return CefString(&settings.accept_language_list);
+  }
+
   return std::string();
 }
 
@@ -295,7 +321,8 @@ std::unique_ptr<PrefService> CreatePrefService(Profile* profile,
 
     // Language preferences. Used by ProfileNetworkContextService and
     // InterceptedRequestHandlerWrapper.
-    const std::string& accept_language_list = GetAcceptLanguageList(profile);
+    const std::string& accept_language_list = GetAcceptLanguageListSetting(
+        CefBrowserContext::FromProfile(profile), /*browser=*/nullptr);
     if (!accept_language_list.empty()) {
       registry->SetDefaultPrefValue(language::prefs::kAcceptLanguages,
                                     base::Value(accept_language_list));
@@ -307,12 +334,26 @@ std::unique_ptr<PrefService> CreatePrefService(Profile* profile,
   return factory.CreateSyncable(registry.get());
 }
 
-void SetLanguagePrefs(Profile* profile) {
-  const std::string& accept_language_list = GetAcceptLanguageList(profile);
-  if (!accept_language_list.empty()) {
-    profile->GetPrefs()->SetString(language::prefs::kAcceptLanguages,
-                                   accept_language_list);
+std::string GetAcceptLanguageList(CefBrowserContext* browser_context,
+                                  CefBrowserHostBase* browser,
+                                  bool expand) {
+  // Always prefer to the CEF settings configuration, if specified.
+  std::string accept_language_list =
+      GetAcceptLanguageListSetting(browser_context, browser);
+  if (accept_language_list.empty() && browser_context) {
+    // Fall back to the preference value. For the Alloy runtime the default
+    // value comes from browser_prefs::CreatePrefService() above. For the Chrome
+    // runtime the default value comes from the configured locale
+    // (IDS_ACCEPT_LANGUAGES) which is then overridden by the user preference in
+    // chrome://settings/languages, all managed by language::LanguagePrefs.
+    auto prefs = browser_context->AsProfile()->GetPrefs();
+    accept_language_list = prefs->GetString(language::prefs::kAcceptLanguages);
   }
+
+  if (!accept_language_list.empty() && expand) {
+    return ComputeAcceptLanguageFromPref(accept_language_list);
+  }
+  return std::string();
 }
 
 }  // namespace browser_prefs

libcef/browser/prefs/browser_prefs.h

@@ -11,6 +11,8 @@ namespace base {
 class FilePath;
 }
 
+class CefBrowserContext;
+class CefBrowserHostBase;
 class PrefRegistrySimple;
 class PrefService;
 class Profile;
@@ -29,8 +31,12 @@ std::unique_ptr<PrefService> CreatePrefService(Profile* profile,
                                                const base::FilePath& cache_path,
                                                bool persist_user_preferences);
 
-// Set language preferences on |profile|.
-void SetLanguagePrefs(Profile* profile);
+// Returns the value for populating the accept-language HTTP request header.
+// |browser_context| and/or |browser| may be nullptr. If |expand| is true then
+// base languages and Q values may be added.
+std::string GetAcceptLanguageList(CefBrowserContext* browser_context,
+                                  CefBrowserHostBase* browser,
+                                  bool expand);
 
 }  // namespace browser_prefs
 

tests/cefclient/browser/main_context_impl.cc

@@ -202,6 +202,12 @@ void MainContextImpl::PopulateSettings(CefSettings* settings) {
 
   if (browser_background_color_ != 0)
     settings->background_color = browser_background_color_;
+
+  if (command_line_->HasSwitch("lang")) {
+    // Use the same locale for the Accept-Language HTTP request header.
+    CefString(&settings->accept_language_list) =
+        command_line_->GetSwitchValue("lang");
+  }
 }
 
 void MainContextImpl::PopulateBrowserSettings(CefBrowserSettings* settings) {