LibWeb+LibWebView+WebContent: Replace DNT with GPC

Global Privacy Control aims to be a replacement for Do Not Track. DNT
ended up not being a great solution, as it wasn't enforced by law. This
actually resulted in the DNT header serving as an extra fingerprinting
data point.

GPC is becoming enforced by law in USA states such as California and
Colorado. CA is further working on a bill which requires that browsers
implement such an opt-out preference signal (OOPS):

https://cppa.ca.gov/announcements/2025/20250911.html

This patch replaces DNT with GPC and hooks up the associated settings.

Libraries/LibWeb/HTML/Navigator.cpp

@@ -134,18 +134,6 @@ WebIDL::Long Navigator::max_touch_points()
     return 0;
 }
 
-// https://www.w3.org/TR/tracking-dnt/#dom-navigator-donottrack
-Optional<FlyString> Navigator::do_not_track() const
-{
-    // The value is null if no DNT header field would be sent (e.g., because a tracking preference is not
-    // enabled and no user-granted exception is applicable); otherwise, the value is a string beginning with
-    // "0" or "1", possibly followed by DNT-extension characters.
-    if (ResourceLoader::the().enable_do_not_track())
-        return "1"_fly_string;
-
-    return {};
-}
-
 GC::Ref<ServiceWorker::ServiceWorkerContainer> Navigator::service_worker()
 {
     if (!m_service_worker_container)

Libraries/LibWeb/HTML/Navigator.h

@@ -8,6 +8,7 @@
 
 #include <LibWeb/Bindings/PlatformObject.h>
 #include <LibWeb/EncryptedMediaExtensions/NavigatorEncryptedMediaExtensionsPartial.h>
+#include <LibWeb/GPC/GlobalPrivacyControl.h>
 #include <LibWeb/Gamepad/NavigatorGamepad.h>
 #include <LibWeb/HTML/MimeTypeArray.h>
 #include <LibWeb/HTML/NavigatorBeacon.h>
@@ -24,11 +25,13 @@
 
 namespace Web::HTML {
 
-class Navigator : public Bindings::PlatformObject
+class Navigator
+    : public Bindings::PlatformObject
     , public NavigatorBeaconPartial
     , public NavigatorConcurrentHardwareMixin
     , public NavigatorDeviceMemoryMixin
     , public Gamepad::NavigatorGamepadPartial
+    , public GlobalPrivacyControl::GlobalPrivacyControlMixin
     , public EncryptedMediaExtensions::NavigatorEncryptedMediaExtensionsPartial
     , public NavigatorIDMixin
     , public NavigatorLanguageMixin
@@ -63,8 +66,6 @@ public:
     [[nodiscard]] GC::Ref<UserActivation> user_activation();
     [[nodiscard]] GC::Ref<CredentialManagement::CredentialsContainer> credentials();
 
-    Optional<FlyString> do_not_track() const;
-
     GC::Ref<ServiceWorker::ServiceWorkerContainer> service_worker();
 
     GC::Ref<MediaCapabilitiesAPI::MediaCapabilities> media_capabilities();

Libraries/LibWeb/HTML/Navigator.idl

@@ -3,6 +3,7 @@
 #import <EncryptedMediaExtensions/MediaKeySystemAccess.idl>
 #import <Gamepad/Gamepad.idl>
 #import <Geolocation/Geolocation.idl>
+#import <GPC/GlobalPrivacyControl.idl>
 #import <HTML/MimeTypeArray.idl>
 #import <HTML/NavigatorBeacon.idl>
 #import <HTML/NavigatorConcurrentHardware.idl>
@@ -37,9 +38,6 @@ interface Navigator {
     // https://html.spec.whatwg.org/multipage/interaction.html#useractivation
     [SameObject] readonly attribute UserActivation userActivation;
 
-    // https://www.w3.org/TR/tracking-dnt/#dom-navigator-donottrack
-    readonly attribute DOMString? doNotTrack;
-
     // https://w3c.github.io/ServiceWorker/#navigator-serviceworker
     [SecureContext, SameObject] readonly attribute ServiceWorkerContainer serviceWorker;
 
@@ -77,6 +75,7 @@ interface mixin NavigatorAutomationInformation {
     readonly attribute boolean webdriver;
 };
 
+Navigator includes GlobalPrivacyControl;
 Navigator includes NavigatorID;
 Navigator includes NavigatorLanguage;
 Navigator includes NavigatorOnLine;

Libraries/LibWeb/HTML/WorkerNavigator.h

@@ -8,6 +8,7 @@
 #pragma once
 
 #include <LibWeb/Bindings/PlatformObject.h>
+#include <LibWeb/GPC/GlobalPrivacyControl.h>
 #include <LibWeb/HTML/NavigatorConcurrentHardware.h>
 #include <LibWeb/HTML/NavigatorDeviceMemory.h>
 #include <LibWeb/HTML/NavigatorID.h>
@@ -20,7 +21,9 @@
 
 namespace Web::HTML {
 
-class WorkerNavigator : public Bindings::PlatformObject
+class WorkerNavigator
+    : public Bindings::PlatformObject
+    , public GlobalPrivacyControl::GlobalPrivacyControlMixin
     , public NavigatorConcurrentHardwareMixin
     , public NavigatorDeviceMemoryMixin
     , public NavigatorIDMixin

Libraries/LibWeb/HTML/WorkerNavigator.idl

@@ -1,3 +1,4 @@
+#import <GPC/GlobalPrivacyControl.idl>
 #import <HTML/NavigatorConcurrentHardware.idl>
 #import <HTML/NavigatorDeviceMemory.idl>
 #import <HTML/NavigatorID.idl>
@@ -20,6 +21,7 @@ interface WorkerNavigator {
     [SecureContext, SameObject] readonly attribute ServiceWorkerContainer serviceWorker;
 };
 
+Navigator includes GlobalPrivacyControl;
 WorkerNavigator includes NavigatorID;
 WorkerNavigator includes NavigatorLanguage;
 WorkerNavigator includes NavigatorOnLine;