LibWeb: Implement Navigator.doNotTrack

(cherry picked from commit 61e616c974ef2deb5edd4f85ae0a3b6da215521a)

Userland/Libraries/LibWeb/HTML/Navigator.cpp

@@ -13,6 +13,7 @@
 #include <LibWeb/HTML/Navigator.h>
 #include <LibWeb/HTML/Scripting/Environments.h>
 #include <LibWeb/HTML/Window.h>
+#include <LibWeb/Loader/ResourceLoader.h>
 #include <LibWeb/Page/Page.h>
 
 namespace Web::HTML {
@@ -100,4 +101,16 @@ 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 {};
+}
+
 }

Userland/Libraries/LibWeb/HTML/Navigator.h

@@ -50,6 +50,8 @@ public:
     [[nodiscard]] JS::NonnullGCPtr<Clipboard::Clipboard> clipboard();
     [[nodiscard]] JS::NonnullGCPtr<UserActivation> user_activation();
 
+    Optional<FlyString> do_not_track() const;
+
     static WebIDL::Long max_touch_points();
 
     virtual ~Navigator() override;

Userland/Libraries/LibWeb/HTML/Navigator.idl

@@ -21,6 +21,9 @@ 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;
 };
 
 // NOTE: As NavigatorContentUtils, NavigatorCookies, NavigatorPlugins, and NavigatorAutomationInformation