LibWeb: Move Web prototypes and constructors to new Intrinsics object

This Intrinsics object hangs off of a new HostDefined struct that takes
the place of EnvironmentSettingsObject as the true [[HostDefined]] slot
on JS::Realm objects created by LibWeb.

This gets the intrinsics off of the GlobalObject, Window, similar to the
previous refactor of LibJS to move the intrinsics into the Realm's
[[Intrinics]] internal slot.

A side effect of this change is that we cannot fully initialize a Window
object until the [[HostDefined]] slot has been installed into the realm,
which happens with the creation of the WindowEnvironmentSettingsObject.

As such, any Window usage that has not been funned through a WindowESO
will not have any cached Web prototyped or constructors, and will not
have Window APIs available to javascript code. Currently this seems
limited to usage of Window in the CSS parser, but a subsequent commit
will clean those up to take Realm as well. However, this commit compiles
so let's cut it off here :^).

Userland/Libraries/LibWeb/HTML/Scripting/Environments.cpp

@@ -286,7 +286,7 @@ EnvironmentSettingsObject& incumbent_settings_object()
     }
 
     // 3. Return context's Realm component's settings object.
-    return verify_cast<EnvironmentSettingsObject>(*context->realm->host_defined());
+    return Bindings::host_defined_environment_settings_object(*context->realm);
 }
 
 // https://html.spec.whatwg.org/multipage/webappapis.html#concept-incumbent-realm
@@ -310,7 +310,7 @@ EnvironmentSettingsObject& current_settings_object()
     auto& vm = event_loop.vm();
 
     // Then, the current settings object is the environment settings object of the current Realm Record.
-    return verify_cast<EnvironmentSettingsObject>(*vm.current_realm()->host_defined());
+    return Bindings::host_defined_environment_settings_object(*vm.current_realm());
 }
 
 // https://html.spec.whatwg.org/multipage/webappapis.html#current-global-object
@@ -334,7 +334,7 @@ JS::Realm& relevant_realm(JS::Object const& object)
 EnvironmentSettingsObject& relevant_settings_object(JS::Object const& object)
 {
     // Then, the relevant settings object for a platform object o is the environment settings object of the relevant Realm for o.
-    return verify_cast<EnvironmentSettingsObject>(*relevant_realm(object).host_defined());
+    return Bindings::host_defined_environment_settings_object(relevant_realm(object));
 }
 
 EnvironmentSettingsObject& relevant_settings_object(DOM::Node const& node)

Userland/Libraries/LibWeb/HTML/Scripting/Environments.h

@@ -54,7 +54,9 @@ enum class RunScriptDecision {
 // https://html.spec.whatwg.org/multipage/webappapis.html#environment-settings-object
 struct EnvironmentSettingsObject
     : public Environment
-    , public JS::Realm::HostDefined {
+    , public JS::Cell {
+    JS_CELL(EnvironmentSettingsObject, JS::Cell);
+
     virtual ~EnvironmentSettingsObject() override;
 
     // https://html.spec.whatwg.org/multipage/webappapis.html#concept-environment-target-browsing-context

Userland/Libraries/LibWeb/HTML/Scripting/WindowEnvironmentSettingsObject.cpp

@@ -4,6 +4,8 @@
  * SPDX-License-Identifier: BSD-2-Clause
  */
 
+#include <LibWeb/Bindings/HostDefined.h>
+#include <LibWeb/Bindings/Intrinsics.h>
 #include <LibWeb/DOM/Document.h>
 #include <LibWeb/HTML/Scripting/WindowEnvironmentSettingsObject.h>
 #include <LibWeb/HTML/Window.h>
@@ -36,7 +38,7 @@ void WindowEnvironmentSettingsObject::setup(AK::URL const& creation_url, Nonnull
 
     // 3. Let settings object be a new environment settings object whose algorithms are defined as follows:
     // NOTE: See the functions defined for this class.
-    auto settings_object = adopt_own(*new WindowEnvironmentSettingsObject(window, move(execution_context)));
+    auto* settings_object = realm->heap().allocate<WindowEnvironmentSettingsObject>(*realm, window, move(execution_context));
 
     // 4. If reservedEnvironment is non-null, then:
     if (reserved_environment.has_value()) {
@@ -68,7 +70,14 @@ void WindowEnvironmentSettingsObject::setup(AK::URL const& creation_url, Nonnull
     settings_object->top_level_origin = top_level_origin;
 
     // 7. Set realm's [[HostDefined]] field to settings object.
-    realm->set_host_defined(move(settings_object));
+    // Non-Standard: We store the ESO next to the web intrinsics in a custom HostDefined object
+    auto* intrinsics = realm->heap().allocate<Bindings::Intrinsics>(*realm, *realm);
+    auto host_defined = make<Bindings::HostDefined>(*settings_object, *intrinsics);
+    realm->set_host_defined(move(host_defined));
+
+    // Non-Standard: We cannot fully initialize window object until *after* the we set up
+    //    the realm's [[HostDefined]] internal slot as the internal slot contains the web platform intrinsics
+    window.initialize_web_interfaces({});
 }
 
 // https://html.spec.whatwg.org/multipage/window-object.html#script-settings-for-window-objects:responsible-document

Userland/Libraries/LibWeb/HTML/Scripting/WindowEnvironmentSettingsObject.h

@@ -12,6 +12,8 @@
 namespace Web::HTML {
 
 class WindowEnvironmentSettingsObject final : public EnvironmentSettingsObject {
+    JS_CELL(WindowEnvironmentSettingsObject, EnvironmentSettingsObject);
+
 public:
     static void setup(AK::URL const& creation_url, NonnullOwnPtr<JS::ExecutionContext>, Optional<Environment>, AK::URL top_level_creation_url, Origin top_level_origin);
 

Userland/Libraries/LibWeb/HTML/Scripting/WorkerEnvironmentSettingsObject.h

@@ -13,23 +13,27 @@
 namespace Web::HTML {
 
 class WorkerEnvironmentSettingsObject final
-    : public EnvironmentSettingsObject
-    , public Weakable<WorkerEnvironmentSettingsObject> {
+    : public EnvironmentSettingsObject {
+    JS_CELL(WindowEnvironmentSettingsObject, EnvironmentSettingsObject);
+
 public:
     WorkerEnvironmentSettingsObject(NonnullOwnPtr<JS::ExecutionContext> execution_context)
         : EnvironmentSettingsObject(move(execution_context))
     {
     }
 
-    static WeakPtr<WorkerEnvironmentSettingsObject> setup(NonnullOwnPtr<JS::ExecutionContext> execution_context /* FIXME: null or an environment reservedEnvironment, a URL topLevelCreationURL, and an origin topLevelOrigin */)
+    static JS::NonnullGCPtr<WorkerEnvironmentSettingsObject> setup(NonnullOwnPtr<JS::ExecutionContext> execution_context /* FIXME: null or an environment reservedEnvironment, a URL topLevelCreationURL, and an origin topLevelOrigin */)
     {
         auto* realm = execution_context->realm;
         VERIFY(realm);
-        auto settings_object = adopt_own(*new WorkerEnvironmentSettingsObject(move(execution_context)));
+        auto settings_object = realm->heap().allocate<WorkerEnvironmentSettingsObject>(*realm, move(execution_context));
         settings_object->target_browsing_context = nullptr;
-        realm->set_host_defined(move(settings_object));
 
-        return static_cast<WorkerEnvironmentSettingsObject*>(realm->host_defined());
+        auto* intrinsics = realm->heap().allocate<Bindings::Intrinsics>(*realm, *realm);
+        auto host_defined = make<Bindings::HostDefined>(*settings_object, *intrinsics);
+        realm->set_host_defined(move(host_defined));
+
+        return *settings_object;
     }
 
     virtual ~WorkerEnvironmentSettingsObject() override = default;