Exposing navigator.language to web workers.

navigator.language should be supported in workers according to
specifications.

This CL adds a virtual function for retrieving the accept_language
to navigator_language which is then overridden by navigator, who gets
the languages from the frame, and woker_navigator, who gets the languages
from renderer preferences. From there, navigator_language parses the
string and returns either the top prefered language or a vector of all
of the preferred languages.

In addition, any changes to the language fires an event that notifies all
of the worker threads to the change, as per specification.

Based on this CL: https://chromium-review.googlesource.com/c/chromium/src/+/1136794

Bug: 276159, 655458
Change-Id: I53bd454f10b5b9b9dc8fd3afa82415b6e93698ca
Reviewed-on: https://chromium-review.googlesource.com/c/1255151
Commit-Queue: Ojan Vafai <ojan@chromium.org>
Reviewed-by: Ojan Vafai <ojan@chromium.org>
Reviewed-by: Tsuyoshi Horo <horo@chromium.org>
Reviewed-by: Dmitry Gozman <dgozman@chromium.org>
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Cr-Commit-Position: refs/heads/master@{#613381}

content/renderer/loader/web_worker_fetch_context_impl.cc

@@ -230,7 +230,8 @@ WebWorkerFetchContextImpl::CloneForNestedWorker() {
   return new_context;
 }
 
-void WebWorkerFetchContextImpl::InitializeOnWorkerThread() {
+void WebWorkerFetchContextImpl::InitializeOnWorkerThread(
+    blink::AcceptLanguagesWatcher* watcher) {
   DCHECK(!resource_dispatcher_);
   DCHECK(!binding_.is_bound());
   DCHECK(!preference_watcher_binding_.is_bound());
@@ -262,6 +263,7 @@ void WebWorkerFetchContextImpl::InitializeOnWorkerThread() {
         base::RefCountedData<blink::mojom::BlobRegistryPtr>>(
         std::move(blob_registry_ptr));
   }
+  accept_languages_watcher_ = watcher;
 
   DCHECK(loader_factory_);
   DCHECK(!web_loader_factory_);
@@ -465,6 +467,9 @@ void WebWorkerFetchContextImpl::ResetServiceWorkerURLLoaderFactory() {
 
 void WebWorkerFetchContextImpl::NotifyUpdate(
     const RendererPreferences& new_prefs) {
+  if (accept_languages_watcher_ &&
+      renderer_preferences_.accept_languages != new_prefs.accept_languages)
+    accept_languages_watcher_->NotifyUpdate();
   renderer_preferences_ = new_prefs;
   child_preference_watchers_.ForAllPtrs(
       [&new_prefs](mojom::RendererPreferenceWatcher* watcher) {
@@ -472,4 +477,8 @@ void WebWorkerFetchContextImpl::NotifyUpdate(
       });
 }
 
+blink::WebString WebWorkerFetchContextImpl::GetAcceptLanguages() const {
+  return blink::WebString::FromUTF8(renderer_preferences_.accept_languages);
+}
+
 }  // namespace content

content/renderer/loader/web_worker_fetch_context_impl.h

@@ -22,6 +22,7 @@
 #include "third_party/blink/public/mojom/blob/blob_registry.mojom.h"
 #include "third_party/blink/public/mojom/service_worker/service_worker_object.mojom.h"
 #include "third_party/blink/public/platform/web_application_cache_host.h"
+#include "third_party/blink/public/platform/web_string.h"
 #include "third_party/blink/public/platform/web_worker_fetch_context.h"
 #include "url/gurl.h"
 
@@ -84,7 +85,7 @@ class CONTENT_EXPORT WebWorkerFetchContextImpl
   // blink::WebWorkerFetchContext implementation:
   scoped_refptr<blink::WebWorkerFetchContext> CloneForNestedWorker() override;
   void SetTerminateSyncLoadEvent(base::WaitableEvent*) override;
-  void InitializeOnWorkerThread() override;
+  void InitializeOnWorkerThread(blink::AcceptLanguagesWatcher*) override;
   blink::WebURLLoaderFactory* GetURLLoaderFactory() override;
   std::unique_ptr<blink::WebURLLoaderFactory> WrapURLLoaderFactory(
       mojo::ScopedMessagePipeHandle url_loader_factory_handle) override;
@@ -131,6 +132,8 @@ class CONTENT_EXPORT WebWorkerFetchContextImpl
   using RewriteURLFunction = blink::WebURL (*)(const std::string&, bool);
   static void InstallRewriteURLFunction(RewriteURLFunction rewrite_url);
 
+  blink::WebString GetAcceptLanguages() const override;
+
  private:
   class Factory;
 
@@ -239,6 +242,8 @@ class CONTENT_EXPORT WebWorkerFetchContextImpl
       websocket_handshake_throttle_provider_;
 
   std::unique_ptr<service_manager::Connector> service_manager_connection_;
+
+  blink::AcceptLanguagesWatcher* accept_languages_watcher_ = nullptr;
 };
 
 }  // namespace content

content/renderer/service_worker/service_worker_fetch_context_impl.cc

@@ -49,7 +49,8 @@ void ServiceWorkerFetchContextImpl::SetTerminateSyncLoadEvent(
   terminate_sync_load_event_ = terminate_sync_load_event;
 }
 
-void ServiceWorkerFetchContextImpl::InitializeOnWorkerThread() {
+void ServiceWorkerFetchContextImpl::InitializeOnWorkerThread(
+    blink::AcceptLanguagesWatcher* watcher) {
   resource_dispatcher_ = std::make_unique<ResourceDispatcher>();
   resource_dispatcher_->set_terminate_sync_load_event(
       terminate_sync_load_event_);
@@ -67,6 +68,8 @@ void ServiceWorkerFetchContextImpl::InitializeOnWorkerThread() {
             network::SharedURLLoaderFactory::Create(
                 std::move(script_loader_factory_info_)));
   }
+
+  accept_languages_watcher_ = watcher;
 }
 
 blink::WebURLLoaderFactory*
@@ -135,7 +138,14 @@ ServiceWorkerFetchContextImpl::CreateWebSocketHandshakeThrottle() {
 
 void ServiceWorkerFetchContextImpl::NotifyUpdate(
     const RendererPreferences& new_prefs) {
+  DCHECK(accept_languages_watcher_);
+  if (renderer_preferences_.accept_languages != new_prefs.accept_languages)
+    accept_languages_watcher_->NotifyUpdate();
   renderer_preferences_ = new_prefs;
 }
 
+blink::WebString ServiceWorkerFetchContextImpl::GetAcceptLanguages() const {
+  return blink::WebString::FromUTF8(renderer_preferences_.accept_languages);
+}
+
 }  // namespace content

content/renderer/service_worker/service_worker_fetch_context_impl.h

@@ -43,7 +43,7 @@ class ServiceWorkerFetchContextImpl final
 
   // blink::WebWorkerFetchContext implementation:
   void SetTerminateSyncLoadEvent(base::WaitableEvent*) override;
-  void InitializeOnWorkerThread() override;
+  void InitializeOnWorkerThread(blink::AcceptLanguagesWatcher*) override;
   blink::WebURLLoaderFactory* GetURLLoaderFactory() override;
   std::unique_ptr<blink::WebURLLoaderFactory> WrapURLLoaderFactory(
       mojo::ScopedMessagePipeHandle url_loader_factory_handle) override;
@@ -54,6 +54,7 @@ class ServiceWorkerFetchContextImpl final
   blink::WebURL SiteForCookies() const override;
   std::unique_ptr<blink::WebSocketHandshakeThrottle>
   CreateWebSocketHandshakeThrottle() override;
+  blink::WebString GetAcceptLanguages() const override;
 
  private:
   ~ServiceWorkerFetchContextImpl() override;
@@ -90,6 +91,8 @@ class ServiceWorkerFetchContextImpl final
 
   // This is owned by ThreadedMessagingProxyBase on the main thread.
   base::WaitableEvent* terminate_sync_load_event_ = nullptr;
+
+  blink::AcceptLanguagesWatcher* accept_languages_watcher_ = nullptr;
 };
 
 }  // namespace content

third_party/blink/public/platform/web_worker_fetch_context.h

@@ -14,6 +14,7 @@
 #include "third_party/blink/public/platform/web_application_cache_host.h"
 #include "third_party/blink/public/platform/web_document_subresource_filter.h"
 #include "third_party/blink/public/platform/web_security_origin.h"
+#include "third_party/blink/public/platform/web_string.h"
 #include "third_party/blink/public/platform/web_url.h"
 #include "third_party/blink/public/platform/web_url_loader_factory.h"
 #include "third_party/blink/public/platform/websocket_handshake_throttle.h"
@@ -27,6 +28,13 @@ namespace blink {
 class WebURLRequest;
 class WebDocumentSubresourceFilter;
 
+// Helper class allowing WebWorkerFetchContextImpl to notify blink upon an
+// accept languages update. This class will be extended by WorkerNavigator.
+class AcceptLanguagesWatcher {
+ public:
+  virtual void NotifyUpdate() = 0;
+};
+
 // WebWorkerFetchContext is a per-worker object created on the main thread,
 // passed to a worker (dedicated, shared and service worker) and initialized on
 // the worker thread by InitializeOnWorkerThread(). It contains information
@@ -58,7 +66,7 @@ class WebWorkerFetchContext : public base::RefCounted<WebWorkerFetchContext> {
   // pointer is valid throughout the lifetime of this context.
   virtual void SetTerminateSyncLoadEvent(base::WaitableEvent*) = 0;
 
-  virtual void InitializeOnWorkerThread() = 0;
+  virtual void InitializeOnWorkerThread(AcceptLanguagesWatcher*) = 0;
 
   // Returns a WebURLLoaderFactory which is associated with the worker context.
   // The returned WebURLLoaderFactory is owned by |this|.
@@ -133,6 +141,9 @@ class WebWorkerFetchContext : public base::RefCounted<WebWorkerFetchContext> {
   CreateWebSocketHandshakeThrottle() {
     return nullptr;
   }
+
+  // Returns the current list of user prefered languages.
+  virtual blink::WebString GetAcceptLanguages() const = 0;
 };
 
 }  // namespace blink

third_party/blink/renderer/core/frame/local_dom_window.cc

@@ -282,7 +282,7 @@ void LocalDOMWindow::ClearDocument() {
 
 void LocalDOMWindow::AcceptLanguagesChanged() {
   if (navigator_)
-    navigator_->SetLanguagesChanged();
+    navigator_->SetLanguagesDirty();
 
   DispatchEvent(*Event::Create(event_type_names::kLanguagechange));
 }

third_party/blink/renderer/core/frame/navigator.cc

@@ -32,13 +32,13 @@
 #include "third_party/blink/renderer/core/loader/frame_loader.h"
 #include "third_party/blink/renderer/core/page/chrome_client.h"
 #include "third_party/blink/renderer/core/page/page.h"
-#include "third_party/blink/renderer/core/probe/core_probes.h"
 #include "third_party/blink/renderer/platform/language.h"
 #include "third_party/blink/renderer/platform/memory_coordinator.h"
 
 namespace blink {
 
-Navigator::Navigator(LocalFrame* frame) : DOMWindowClient(frame) {}
+Navigator::Navigator(LocalFrame* frame)
+    : NavigatorLanguage(frame->GetDocument()), DOMWindowClient(frame) {}
 
 String Navigator::productSub() const {
   return "20030107";
@@ -83,38 +83,21 @@ bool Navigator::cookieEnabled() const {
   return CookiesEnabled(GetFrame()->GetDocument());
 }
 
-Vector<String> Navigator::languages() {
-  languages_changed_ = false;
-
+String Navigator::GetAcceptLanguages() {
   String accept_languages;
   if (GetFrame() && GetFrame()->GetPage()) {
     accept_languages =
         GetFrame()->GetPage()->GetChromeClient().AcceptLanguages();
+  } else {
+    accept_languages = DefaultLanguage();
   }
 
-  probe::applyAcceptLanguageOverride(GetFrame(), &accept_languages);
-
-  Vector<String> languages;
-  accept_languages.Split(',', languages);
-
-  // Sanitizing tokens. We could do that more extensively but we should assume
-  // that the accept languages are already sane and support BCP47. It is
-  // likely a waste of time to make sure the tokens matches that spec here.
-  for (wtf_size_t i = 0; i < languages.size(); ++i) {
-    String& token = languages[i];
-    token = token.StripWhiteSpace();
-    if (token.length() >= 3 && token[2] == '_')
-      token.replace(2, 1, "-");
-  }
-
-  if (languages.IsEmpty())
-    languages.push_back(DefaultLanguage());
-
-  return languages;
+  return accept_languages;
 }
 
 void Navigator::Trace(blink::Visitor* visitor) {
   ScriptWrappable::Trace(visitor);
+  NavigatorLanguage::Trace(visitor);
   DOMWindowClient::Trace(visitor);
   Supplementable<Navigator>::Trace(visitor);
 }

third_party/blink/renderer/core/frame/navigator.h

@@ -66,8 +66,7 @@ class CORE_EXPORT Navigator final : public ScriptWrappable,
   String platform() const override;
   String userAgent() const override;
 
-  // NavigatorLanguage
-  Vector<String> languages() override;
+  String GetAcceptLanguages() override;
 
   void Trace(blink::Visitor*) override;
 };

third_party/blink/renderer/core/frame/navigator_language.cc

@@ -4,22 +4,65 @@
 
 #include "third_party/blink/renderer/core/frame/navigator_language.h"
 
+#include "third_party/blink/renderer/core/probe/core_probes.h"
 #include "third_party/blink/renderer/platform/language.h"
 
 namespace blink {
 
-NavigatorLanguage::NavigatorLanguage() = default;
+Vector<String> ParseAndSanitize(const String& accept_languages) {
+  Vector<String> languages;
+  accept_languages.Split(',', languages);
+
+  // Sanitizing tokens. We could do that more extensively but we should assume
+  // that the accept languages are already sane and support BCP47. It is
+  // likely a waste of time to make sure the tokens matches that spec here.
+  for (size_t i = 0; i < languages.size(); ++i) {
+    String& token = languages[i];
+    token = token.StripWhiteSpace();
+    if (token.length() >= 3 && token[2] == '_')
+      token.replace(2, 1, "-");
+  }
+
+  if (languages.IsEmpty())
+    languages.push_back(DefaultLanguage());
+
+  return languages;
+}
+
+NavigatorLanguage::NavigatorLanguage(ExecutionContext* context)
+    : context_(context) {}
 
 AtomicString NavigatorLanguage::language() {
   return AtomicString(languages().front());
 }
 
-bool NavigatorLanguage::hasLanguagesChanged() const {
-  return languages_changed_;
+const Vector<String>& NavigatorLanguage::languages() {
+  if (languages_dirty_) {
+    String accept_languages_override;
+    probe::applyAcceptLanguageOverride(context_, &accept_languages_override);
+
+    if (!accept_languages_override.IsNull()) {
+      languages_ = ParseAndSanitize(accept_languages_override);
+    } else {
+      languages_ = ParseAndSanitize(GetAcceptLanguages());
+    }
+
+    languages_dirty_ = false;
+  }
+  return languages_;
+}
+
+bool NavigatorLanguage::IsLanguagesDirty() const {
+  return languages_dirty_;
+}
+
+void NavigatorLanguage::SetLanguagesDirty() {
+  languages_dirty_ = true;
+  languages_.clear();
 }
 
-void NavigatorLanguage::SetLanguagesChanged() {
-  languages_changed_ = true;
+void NavigatorLanguage::Trace(blink::Visitor* visitor) {
+  visitor->Trace(context_);
 }
 
 }  // namespace blink

third_party/blink/renderer/core/frame/navigator_language.h

@@ -6,21 +6,29 @@
 #define THIRD_PARTY_BLINK_RENDERER_CORE_FRAME_NAVIGATOR_LANGUAGE_H_
 
 #include "third_party/blink/renderer/core/core_export.h"
+#include "third_party/blink/renderer/core/execution_context/execution_context.h"
 #include "third_party/blink/renderer/platform/wtf/text/atomic_string.h"
 
 namespace blink {
 
-class CORE_EXPORT NavigatorLanguage {
+class CORE_EXPORT NavigatorLanguage : public GarbageCollectedMixin {
  public:
-  NavigatorLanguage();
+  explicit NavigatorLanguage(ExecutionContext*);
 
   AtomicString language();
-  virtual Vector<String> languages() = 0;
-  bool hasLanguagesChanged() const;
-  void SetLanguagesChanged();
+  const Vector<String>& languages();
+  bool IsLanguagesDirty() const;
+  void SetLanguagesDirty();
+
+  void Trace(blink::Visitor*) override;
 
  protected:
-  bool languages_changed_ = true;
+  bool languages_dirty_ = true;
+  WeakMember<ExecutionContext> context_;
+  virtual String GetAcceptLanguages() = 0;
+
+ private:
+  Vector<String> languages_;
 };
 
 }  // namespace blink

third_party/blink/renderer/core/frame/navigator_language.idl

@@ -9,5 +9,5 @@
     Exposed=(Window,Worker)
 ] interface NavigatorLanguage {
     readonly attribute DOMString language;
-    [CachedAttribute=hasLanguagesChanged] readonly attribute FrozenArray<DOMString> languages;
+    [CachedAttribute=IsLanguagesDirty] readonly attribute FrozenArray<DOMString> languages;
 };

third_party/blink/renderer/core/inspector/worker_inspector_controller.cc

@@ -110,7 +110,7 @@ void WorkerInspectorController::AttachSession(DevToolsSession* session,
   session->Append(MakeGarbageCollected<InspectorLogAgent>(
       thread_->GetConsoleMessageStorage(), nullptr, session->V8Session()));
   if (auto* scope = DynamicTo<WorkerGlobalScope>(thread_->GlobalScope())) {
-    DCHECK(scope->EnsureFetcher());
+    scope->EnsureFetcher();
     session->Append(MakeGarbageCollected<InspectorNetworkAgent>(
         inspected_frames_.Get(), scope, session->V8Session()));
     session->Append(MakeGarbageCollected<InspectorEmulationAgent>(nullptr));

third_party/blink/renderer/core/probe/core_probes.pidl

@@ -87,7 +87,7 @@ interface CoreProbes {
   void didFireWebGLErrorOrWarning(Element*, const String& message);
   void didResizeMainFrame(LocalFrame*);
   void didPaint(LocalFrame*, const GraphicsLayer*, GraphicsContext&, const LayoutRect&);
-  void applyAcceptLanguageOverride(LocalFrame*, String* acceptLanguage);
+  void applyAcceptLanguageOverride(ExecutionContext*, String* acceptLanguage);
   void applyUserAgentOverride(ExecutionContext*, String* userAgent);
   void didBlockRequest([Keep] ExecutionContext*, const ResourceRequest&, DocumentLoader*, const FetchInitiatorInfo&, ResourceRequestBlockedReason, ResourceType);
   void didChangeResourcePriority(LocalFrame*, DocumentLoader*, unsigned long identifier, ResourceLoadPriority loadPriority);

third_party/blink/renderer/core/workers/worker_global_scope.cc

@@ -123,7 +123,7 @@ WorkerLocation* WorkerGlobalScope::location() const {
 
 WorkerNavigator* WorkerGlobalScope::navigator() const {
   if (!navigator_)
-    navigator_ = WorkerNavigator::Create(user_agent_);
+    navigator_ = WorkerNavigator::Create(user_agent_, GetExecutionContext());
   return navigator_.Get();
 }
 

third_party/blink/renderer/core/workers/worker_global_scope.h

@@ -93,7 +93,7 @@ class CORE_EXPORT WorkerGlobalScope
   // WorkerGlobalScope
   WorkerGlobalScope* self() { return this; }
   WorkerLocation* location() const;
-  WorkerNavigator* navigator() const;
+  WorkerNavigator* navigator() const override;
   void close();
   bool isSecureContextForBindings() const {
     return ExecutionContext::IsSecureContext();
@@ -102,6 +102,7 @@ class CORE_EXPORT WorkerGlobalScope
   String origin() const;
 
   DEFINE_ATTRIBUTE_EVENT_LISTENER(error, kError);
+  DEFINE_ATTRIBUTE_EVENT_LISTENER(languagechange, kLanguagechange);
   DEFINE_ATTRIBUTE_EVENT_LISTENER(rejectionhandled, kRejectionhandled);
   DEFINE_ATTRIBUTE_EVENT_LISTENER(unhandledrejection, kUnhandledrejection);
 

third_party/blink/renderer/core/workers/worker_global_scope.idl

@@ -36,7 +36,7 @@
 
     // TODO(foolip): onerror should be an OnErrorEventHandler.
     attribute EventHandler onerror;
-    // attribute EventHandler onlanguagechange;
+    attribute EventHandler onlanguagechange;
     // attribute EventHandler onoffline;
     // attribute EventHandler ononline;
 

third_party/blink/renderer/core/workers/worker_navigator.cc

@@ -25,11 +25,20 @@
  */
 
 #include "third_party/blink/renderer/core/workers/worker_navigator.h"
+#include "third_party/blink/public/platform/web_worker_fetch_context.h"
+#include "third_party/blink/renderer/core/dom/events/event.h"
+#include "third_party/blink/renderer/core/dom/events/event_target.h"
+#include "third_party/blink/renderer/core/loader/worker_fetch_context.h"
+#include "third_party/blink/renderer/core/workers/worker_global_scope.h"
+#include "third_party/blink/renderer/core/workers/worker_or_worklet_global_scope.h"
+#include "third_party/blink/renderer/core/workers/worker_thread.h"
+#include "third_party/blink/renderer/platform/loader/fetch/resource_fetcher.h"
 
 namespace blink {
 
-WorkerNavigator::WorkerNavigator(const String& user_agent)
-    : user_agent_(user_agent) {}
+WorkerNavigator::WorkerNavigator(const String& user_agent,
+                                 ExecutionContext* context)
+    : NavigatorLanguage(context), user_agent_(user_agent) {}
 
 WorkerNavigator::~WorkerNavigator() = default;
 
@@ -37,8 +46,27 @@ String WorkerNavigator::userAgent() const {
   return user_agent_;
 }
 
+String WorkerNavigator::GetAcceptLanguages() {
+  WorkerOrWorkletGlobalScope* global_scope =
+      To<WorkerOrWorkletGlobalScope>(context_.Get());
+  WebWorkerFetchContext* worker_fetch_context =
+      static_cast<WorkerFetchContext*>(
+          (&global_scope->EnsureFetcher()->Context()))
+          ->GetWebWorkerFetchContext();
+  return worker_fetch_context->GetAcceptLanguages();
+}
+
+void WorkerNavigator::NotifyUpdate() {
+  SetLanguagesDirty();
+  WorkerOrWorkletGlobalScope* global_scope =
+      To<WorkerOrWorkletGlobalScope>(context_.Get());
+  global_scope->DispatchEvent(
+      *Event::Create(event_type_names::kLanguagechange));
+}
+
 void WorkerNavigator::Trace(blink::Visitor* visitor) {
   ScriptWrappable::Trace(visitor);
+  NavigatorLanguage::Trace(visitor);
   Supplementable<WorkerNavigator>::Trace(visitor);
 }
 

third_party/blink/renderer/core/workers/worker_navigator.h

@@ -26,10 +26,13 @@
 #ifndef THIRD_PARTY_BLINK_RENDERER_CORE_WORKERS_WORKER_NAVIGATOR_H_
 #define THIRD_PARTY_BLINK_RENDERER_CORE_WORKERS_WORKER_NAVIGATOR_H_
 
+#include "third_party/blink/public/platform/web_worker_fetch_context.h"
 #include "third_party/blink/renderer/core/core_export.h"
+#include "third_party/blink/renderer/core/execution_context/execution_context.h"
 #include "third_party/blink/renderer/core/frame/navigator_concurrent_hardware.h"
 #include "third_party/blink/renderer/core/frame/navigator_device_memory.h"
 #include "third_party/blink/renderer/core/frame/navigator_id.h"
+#include "third_party/blink/renderer/core/frame/navigator_language.h"
 #include "third_party/blink/renderer/core/frame/navigator_on_line.h"
 #include "third_party/blink/renderer/platform/bindings/script_wrappable.h"
 #include "third_party/blink/renderer/platform/heap/handle.h"
@@ -40,24 +43,34 @@ namespace blink {
 
 class CORE_EXPORT WorkerNavigator final
     : public ScriptWrappable,
+      public AcceptLanguagesWatcher,
       public NavigatorConcurrentHardware,
       public NavigatorDeviceMemory,
       public NavigatorID,
+      public NavigatorLanguage,
       public NavigatorOnLine,
       public Supplementable<WorkerNavigator> {
   DEFINE_WRAPPERTYPEINFO();
   USING_GARBAGE_COLLECTED_MIXIN(WorkerNavigator);
 
  public:
-  static WorkerNavigator* Create(const String& user_agent) {
-    return MakeGarbageCollected<WorkerNavigator>(user_agent);
+  static WorkerNavigator* Create(const String& user_agent,
+                                 ExecutionContext* context) {
+    return MakeGarbageCollected<WorkerNavigator>(user_agent, context);
   }
 
-  explicit WorkerNavigator(const String&);
+  explicit WorkerNavigator(const String&, ExecutionContext* context);
   ~WorkerNavigator() override;
 
+  // NavigatorID override
   String userAgent() const override;
 
+  // NavigatorLanguage override
+  String GetAcceptLanguages() override;
+
+  // AcceptLanguagesWatcher override
+  void NotifyUpdate() override;
+
   void Trace(blink::Visitor*) override;
 
  private:

third_party/blink/renderer/core/workers/worker_navigator.idl

@@ -36,5 +36,5 @@
 WorkerNavigator implements NavigatorConcurrentHardware;
 WorkerNavigator implements NavigatorDeviceMemory;
 WorkerNavigator implements NavigatorID;
-// TODO(foolip): WorkerNavigator implements NavigatorLanguage;
+WorkerNavigator implements NavigatorLanguage;
 WorkerNavigator implements NavigatorOnLine;

third_party/blink/renderer/core/workers/worker_or_worklet_global_scope.cc

@@ -15,6 +15,7 @@
 #include "third_party/blink/renderer/core/loader/worker_fetch_context.h"
 #include "third_party/blink/renderer/core/probe/core_probes.h"
 #include "third_party/blink/renderer/core/script/fetch_client_settings_object_impl.h"
+#include "third_party/blink/renderer/core/workers/worker_global_scope.h"
 #include "third_party/blink/renderer/core/workers/worker_reporting_proxy.h"
 #include "third_party/blink/renderer/core/workers/worker_thread.h"
 #include "third_party/blink/renderer/platform/cross_thread_functional.h"
@@ -108,7 +109,7 @@ void WorkerOrWorkletGlobalScope::InitializeWebFetchContextIfNeeded() {
     return;
 
   DCHECK(!subresource_filter_);
-  web_worker_fetch_context_->InitializeOnWorkerThread();
+  web_worker_fetch_context_->InitializeOnWorkerThread(navigator());
   std::unique_ptr<blink::WebDocumentSubresourceFilter> web_filter =
       web_worker_fetch_context_->TakeSubresourceFilter();
   if (web_filter) {

third_party/blink/renderer/core/workers/worker_or_worklet_global_scope.h

@@ -17,6 +17,7 @@
 #include "third_party/blink/renderer/core/frame/web_feature_forward.h"
 #include "third_party/blink/renderer/core/script/modulator.h"
 #include "third_party/blink/renderer/core/workers/worker_clients.h"
+#include "third_party/blink/renderer/core/workers/worker_navigator.h"
 #include "third_party/blink/renderer/platform/scheduler/public/worker_scheduler.h"
 #include "third_party/blink/renderer/platform/wtf/bit_vector.h"
 #include "third_party/blink/renderer/platform/wtf/casting.h"
@@ -91,6 +92,9 @@ class CORE_EXPORT WorkerOrWorkletGlobalScope : public EventTargetWithInlineData,
   // WorkletGlobalScope for the main thread) or after Dispose() is called.
   virtual WorkerThread* GetThread() const = 0;
 
+  // Returns nullptr if this global scope is a WorkletGlobalScope
+  virtual WorkerNavigator* navigator() const { return nullptr; }
+
   ResourceFetcher* Fetcher() const override;
   ResourceFetcher* EnsureFetcher();
 

third_party/blink/renderer/core/workers/worker_thread.h

@@ -41,6 +41,7 @@
 #include "third_party/blink/renderer/core/frame/csp/content_security_policy.h"
 #include "third_party/blink/renderer/core/workers/parent_execution_context_task_runners.h"
 #include "third_party/blink/renderer/core/workers/worker_backing_thread_startup_data.h"
+#include "third_party/blink/renderer/platform/cross_thread_functional.h"
 #include "third_party/blink/renderer/platform/scheduler/public/post_cancellable_task.h"
 #include "third_party/blink/renderer/platform/scheduler/public/post_cross_thread_task.h"
 #include "third_party/blink/renderer/platform/scheduler/public/thread.h"

third_party/blink/web_tests/TestExpectations

@@ -4160,6 +4160,8 @@ crbug.com/655458 virtual/omt-worker-fetch/external/wpt/workers/constructors/Shar
 crbug.com/655458 virtual/omt-worker-fetch/external/wpt/workers/constructors/SharedWorker/unresolvable-url.html [ Failure ]
 crbug.com/655458 virtual/omt-worker-fetch/external/wpt/workers/semantics/multiple-workers/007.html [ Timeout ]
 
+crbug.com/910709 navigator_language/worker_navigator_language.html [ Timeout ]
+
 # Off-the-main-thread classic worker script fetch.
 # This fails because running a worker on an opaque origin is blocked.
 crbug.com/835717 virtual/omt-worker-fetch/external/wpt/workers/opaque-origin.html [ Timeout ]

third_party/blink/web_tests/external/wpt/workers/interfaces.worker-expected.txt

 This is a testharness.js-based test.
-Found 161 tests; 151 PASS, 10 FAIL, 0 TIMEOUT, 0 NOTRUN.
+Found 161 tests; 157 PASS, 4 FAIL, 0 TIMEOUT, 0 NOTRUN.
 PASS EventTarget interface: existence and properties of interface object
 PASS EventTarget interface object length
 PASS EventTarget interface object name
@@ -21,7 +21,7 @@ PASS WorkerGlobalScope interface: attribute location
 PASS WorkerGlobalScope interface: attribute navigator
 PASS WorkerGlobalScope interface: operation importScripts(USVString)
 PASS WorkerGlobalScope interface: attribute onerror
-FAIL WorkerGlobalScope interface: attribute onlanguagechange assert_true: The prototype object must have a property "onlanguagechange" expected true got false
+PASS WorkerGlobalScope interface: attribute onlanguagechange
 FAIL WorkerGlobalScope interface: attribute onoffline assert_true: The prototype object must have a property "onoffline" expected true got false
 FAIL WorkerGlobalScope interface: attribute ononline assert_true: The prototype object must have a property "ononline" expected true got false
 PASS WorkerGlobalScope interface: attribute onrejectionhandled
@@ -72,7 +72,7 @@ PASS WorkerGlobalScope interface: self must inherit property "navigator" with th
 PASS WorkerGlobalScope interface: self must inherit property "importScripts(USVString)" with the proper type
 PASS WorkerGlobalScope interface: calling importScripts(USVString) on self with too few arguments must throw TypeError
 PASS WorkerGlobalScope interface: self must inherit property "onerror" with the proper type
-FAIL WorkerGlobalScope interface: self must inherit property "onlanguagechange" with the proper type assert_inherits: property "onlanguagechange" not found in prototype chain
+PASS WorkerGlobalScope interface: self must inherit property "onlanguagechange" with the proper type
 FAIL WorkerGlobalScope interface: self must inherit property "onoffline" with the proper type assert_inherits: property "onoffline" not found in prototype chain
 FAIL WorkerGlobalScope interface: self must inherit property "ononline" with the proper type assert_inherits: property "ononline" not found in prototype chain
 PASS WorkerGlobalScope interface: self must inherit property "onrejectionhandled" with the proper type
@@ -115,8 +115,8 @@ PASS WorkerNavigator interface: member productSub
 PASS WorkerNavigator interface: attribute userAgent
 PASS WorkerNavigator interface: member vendor
 PASS WorkerNavigator interface: member vendorSub
-FAIL WorkerNavigator interface: attribute language assert_true: The prototype object must have a property "language" expected true got false
-FAIL WorkerNavigator interface: attribute languages assert_true: The prototype object must have a property "languages" expected true got false
+PASS WorkerNavigator interface: attribute language
+PASS WorkerNavigator interface: attribute languages
 PASS WorkerNavigator interface: attribute onLine
 PASS WorkerNavigator interface: attribute hardwareConcurrency
 PASS WorkerNavigator must be primary interface of self.navigator
@@ -130,8 +130,8 @@ PASS WorkerNavigator interface: self.navigator must not have property "productSu
 PASS WorkerNavigator interface: self.navigator must inherit property "userAgent" with the proper type
 PASS WorkerNavigator interface: self.navigator must not have property "vendor"
 PASS WorkerNavigator interface: self.navigator must not have property "vendorSub"
-FAIL WorkerNavigator interface: self.navigator must inherit property "language" with the proper type assert_inherits: property "language" not found in prototype chain
-FAIL WorkerNavigator interface: self.navigator must inherit property "languages" with the proper type assert_inherits: property "languages" not found in prototype chain
+PASS WorkerNavigator interface: self.navigator must inherit property "language" with the proper type
+PASS WorkerNavigator interface: self.navigator must inherit property "languages" with the proper type
 PASS WorkerNavigator interface: self.navigator must inherit property "onLine" with the proper type
 PASS WorkerNavigator interface: self.navigator must inherit property "hardwareConcurrency" with the proper type
 PASS WorkerLocation interface: existence and properties of interface object

third_party/blink/web_tests/http/tests/inspector-protocol/emulation/emulation-user-agent-override-expected.txt

@@ -2,6 +2,7 @@ Tests emulation of the user agent.
 navigator.userAgent == Test UA
 User-Agent: Test UA
 navigator.language == ko
+workerNavigator.language == ko
 Accept-Language: ko, en;q=0.9, zh-CN;q=0.8, zh-HK;q=0.7, en-US;q=0.6, en-GB;q=0.5
 accept-language: ko
 navigator.platform == new_platform

third_party/blink/web_tests/http/tests/inspector-protocol/emulation/emulation-user-agent-override.js

@@ -9,6 +9,18 @@
   // Accept Language
   await dp.Emulation.setUserAgentOverride({userAgent: '', acceptLanguage: 'ko, en, zh-CN, zh-HK, en-US, en-GB'});
   testRunner.log('navigator.language == ' + await session.evaluate('navigator.language'));
+
+  // Worker Accept Language
+  await dp.Target.setAutoAttach({autoAttach: true, waitForDebuggerOnStart: false});
+  await session.evaluate(`var w = new Worker('${testRunner.url('resources/worker.js')}')`);
+  let event = await dp.Target.onceAttachedToTarget();
+  const worker = new WorkerProtocol(dp, event.params.sessionId);
+  await worker.dp.Emulation.setUserAgentOverride({userAgent: '', acceptLanguage: 'ko, en, zh-CN, zh-HK, en-US, en-GB'});
+  testRunner.log('workerNavigator.language == ' + await session.evaluateAsync(`
+      w.postMessage('ping!');
+      new Promise(resolve => w.onmessage = e => resolve(e.data.language))`));
+  await dp.Target.onceDetachedFromTarget();
+
   await printHeader('Accept-Language');
 
   // Do not override explicit Accept-Language header.

third_party/blink/web_tests/http/tests/inspector-protocol/emulation/resources/worker.js

+onmessage = function(e) {
+  postMessage({'language': navigator.language});
+  close();
+};

third_party/blink/web_tests/http/tests/serviceworker/webexposed/global-interface-listing-service-worker-expected.txt

@@ -3446,6 +3446,7 @@ interface WorkerGlobalScope : EventTarget
     getter location
     getter navigator
     getter onerror
+    getter onlanguagechange
     getter onrejectionhandled
     getter onunhandledrejection
     getter origin
@@ -3465,6 +3466,7 @@ interface WorkerGlobalScope : EventTarget
     method setInterval
     method setTimeout
     setter onerror
+    setter onlanguagechange
     setter onrejectionhandled
     setter onunhandledrejection
     setter origin
@@ -3490,6 +3492,8 @@ interface WorkerNavigator
     getter connection
     getter deviceMemory
     getter hardwareConcurrency
+    getter language
+    getter languages
     getter locks
     getter onLine
     getter permissions

third_party/blink/web_tests/navigator_language/resources/worker_language.js

+onmessage = function(evt)
+{
+  postMessage(navigator.language);
+}

third_party/blink/web_tests/navigator_language/resources/worker_language_event.js

+onlanguagechange = function(evt)
+{
+  postMessage('language event fired');
+}

third_party/blink/web_tests/navigator_language/worker_navigator_language.html

+<!DOCTYPE html>
+<html>
+<body>
+<script src="../resources/testharness.js"></script>
+<script src="../resources/testharnessreport.js"></script>
+<script>
+
+async_test(function() {
+    var worker = new Worker("resources/worker_language.js");
+    worker.onmessage = this.step_func_done(function(e) {
+        assert_equals(e.data, 'klingon');
+    });
+    testRunner.setAcceptLanguages('klingon');
+    worker.postMessage("langauge changed");
+    done();
+}, "Test changing the language on worker threads.");
+
+async_test(function() {
+    var worker = new Worker("resources/worker_language_event.js");
+    worker.onmessage = this.step_func_done(function(e) {
+        assert_equals(e.data, 'language event fired');
+    });
+    testRunner.setAcceptLanguages('fr-FR');
+    done();
+}, "Test the language change event fires on worker threads.");
+
+async_test(function() {
+    var worker = new Worker("resources/worker_language.js");
+    var previous = navigator.languages
+    worker.onmessage = this.step_func_done(function(e) {
+        assert_equals(e.data, previous);
+    });
+    worker.postMessage("same language");
+     worker.onmessage = this.step_func_done(function(e) {
+        assert_not_equals(e.data, previous);
+     });
+    testRunner.setAcceptLanguages('fr-FR');
+    worker.postMessage("different language");
+    done();
+}, "Test caching behavior on worker threads");
+
+</script>
+</body>
+</html>

third_party/blink/web_tests/virtual/stable/http/tests/serviceworker/webexposed/global-interface-listing-service-worker-expected.txt

@@ -2447,6 +2447,7 @@ interface WorkerGlobalScope : EventTarget
     getter location
     getter navigator
     getter onerror
+    getter onlanguagechange
     getter onrejectionhandled
     getter onunhandledrejection
     getter origin
@@ -2466,6 +2467,7 @@ interface WorkerGlobalScope : EventTarget
     method setInterval
     method setTimeout
     setter onerror
+    setter onlanguagechange
     setter onrejectionhandled
     setter onunhandledrejection
     setter origin
@@ -2491,6 +2493,8 @@ interface WorkerNavigator
     getter connection
     getter deviceMemory
     getter hardwareConcurrency
+    getter language
+    getter languages
     getter locks
     getter onLine
     getter permissions

third_party/blink/web_tests/virtual/stable/webexposed/global-interface-listing-dedicated-worker-expected.txt

@@ -2491,6 +2491,7 @@ Starting worker: resources/global-interface-listing-worker.js
 [Worker]     getter location
 [Worker]     getter navigator
 [Worker]     getter onerror
+[Worker]     getter onlanguagechange
 [Worker]     getter onrejectionhandled
 [Worker]     getter onunhandledrejection
 [Worker]     getter origin
@@ -2510,6 +2511,7 @@ Starting worker: resources/global-interface-listing-worker.js
 [Worker]     method setInterval
 [Worker]     method setTimeout
 [Worker]     setter onerror
+[Worker]     setter onlanguagechange
 [Worker]     setter onrejectionhandled
 [Worker]     setter onunhandledrejection
 [Worker]     setter origin
@@ -2535,6 +2537,8 @@ Starting worker: resources/global-interface-listing-worker.js
 [Worker]     getter connection
 [Worker]     getter deviceMemory
 [Worker]     getter hardwareConcurrency
+[Worker]     getter language
+[Worker]     getter languages
 [Worker]     getter locks
 [Worker]     getter onLine
 [Worker]     getter permissions

third_party/blink/web_tests/virtual/stable/webexposed/global-interface-listing-shared-worker-expected.txt

@@ -2378,6 +2378,7 @@ Starting worker: resources/global-interface-listing-worker.js
 [Worker]     getter location
 [Worker]     getter navigator
 [Worker]     getter onerror
+[Worker]     getter onlanguagechange
 [Worker]     getter onrejectionhandled
 [Worker]     getter onunhandledrejection
 [Worker]     getter origin
@@ -2397,6 +2398,7 @@ Starting worker: resources/global-interface-listing-worker.js
 [Worker]     method setInterval
 [Worker]     method setTimeout
 [Worker]     setter onerror
+[Worker]     setter onlanguagechange
 [Worker]     setter onrejectionhandled
 [Worker]     setter onunhandledrejection
 [Worker]     setter origin
@@ -2422,6 +2424,8 @@ Starting worker: resources/global-interface-listing-worker.js
 [Worker]     getter connection
 [Worker]     getter deviceMemory
 [Worker]     getter hardwareConcurrency
+[Worker]     getter language
+[Worker]     getter languages
 [Worker]     getter locks
 [Worker]     getter onLine
 [Worker]     getter permissions

third_party/blink/web_tests/webexposed/global-interface-listing-dedicated-worker-expected.txt

@@ -3476,6 +3476,7 @@ Starting worker: resources/global-interface-listing-worker.js
 [Worker]     getter location
 [Worker]     getter navigator
 [Worker]     getter onerror
+[Worker]     getter onlanguagechange
 [Worker]     getter onrejectionhandled
 [Worker]     getter onunhandledrejection
 [Worker]     getter origin
@@ -3495,6 +3496,7 @@ Starting worker: resources/global-interface-listing-worker.js
 [Worker]     method setInterval
 [Worker]     method setTimeout
 [Worker]     setter onerror
+[Worker]     setter onlanguagechange
 [Worker]     setter onrejectionhandled
 [Worker]     setter onunhandledrejection
 [Worker]     setter origin
@@ -3520,6 +3522,8 @@ Starting worker: resources/global-interface-listing-worker.js
 [Worker]     getter connection
 [Worker]     getter deviceMemory
 [Worker]     getter hardwareConcurrency
+[Worker]     getter language
+[Worker]     getter languages
 [Worker]     getter locks
 [Worker]     getter onLine
 [Worker]     getter permissions

third_party/blink/web_tests/webexposed/global-interface-listing-shared-worker-expected.txt

@@ -3348,6 +3348,7 @@ Starting worker: resources/global-interface-listing-worker.js
 [Worker]     getter location
 [Worker]     getter navigator
 [Worker]     getter onerror
+[Worker]     getter onlanguagechange
 [Worker]     getter onrejectionhandled
 [Worker]     getter onunhandledrejection
 [Worker]     getter origin
@@ -3367,6 +3368,7 @@ Starting worker: resources/global-interface-listing-worker.js
 [Worker]     method setInterval
 [Worker]     method setTimeout
 [Worker]     setter onerror
+[Worker]     setter onlanguagechange
 [Worker]     setter onrejectionhandled
 [Worker]     setter onunhandledrejection
 [Worker]     setter origin
@@ -3392,6 +3394,8 @@ Starting worker: resources/global-interface-listing-worker.js
 [Worker]     getter connection
 [Worker]     getter deviceMemory
 [Worker]     getter hardwareConcurrency
+[Worker]     getter language
+[Worker]     getter languages
 [Worker]     getter locks
 [Worker]     getter onLine
 [Worker]     getter permissions