LibWeb: Re-implement HTML::Navigator using IDL

Get rid of the bespoke NavigatorObject class and use the modern IDL
strategies for creating platform objects to re-implement Navigator and
its associcated mixin interfaces. While we're here, implement it in a
way that brings WorkerNavigator up to spec :^)

Userland/Libraries/LibWeb/HTML/Navigator.h

@@ -0,0 +1,48 @@
+/*
+ * Copyright (c) 2022, Andrew Kaster <akaster@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <LibWeb/Bindings/PlatformObject.h>
+#include <LibWeb/HTML/NavigatorConcurrentHardware.h>
+#include <LibWeb/HTML/NavigatorID.h>
+#include <LibWeb/HTML/NavigatorLanguage.h>
+#include <LibWeb/HTML/NavigatorOnLine.h>
+
+namespace Web::HTML {
+
+class Navigator : public Bindings::PlatformObject
+    , public NavigatorConcurrentHardwareMixin
+    , public NavigatorIDMixin
+    , public NavigatorLanguageMixin
+    , public NavigatorOnLineMixin {
+    WEB_PLATFORM_OBJECT(Navigator, Bindings::PlatformObject);
+
+public:
+    static JS::NonnullGCPtr<Navigator> create(JS::Realm&);
+
+    // FIXME: Implement NavigatorContentUtilsMixin
+
+    // NavigatorCookies
+    // FIXME: Hook up to Agent level state
+    // https://html.spec.whatwg.org/multipage/system-state.html#dom-navigator-cookieenabled
+    bool cookie_enabled() const { return true; }
+
+    // NavigatorPlugins
+    // FIXME: Actually support pdf viewing
+    // https://html.spec.whatwg.org/multipage/system-state.html#dom-navigator-javaenabled
+    bool java_enabled() const { return false; }
+
+    // https://html.spec.whatwg.org/multipage/system-state.html#dom-navigator-pdfviewerenabled
+    bool pdf_viewer_enabled() const { return false; }
+
+    virtual ~Navigator() override;
+
+private:
+    explicit Navigator(JS::Realm&);
+};
+
+}