LibWeb+LibJS: Make the EventTarget hierarchy (incl. DOM) GC-allocated

This is a monster patch that turns all EventTargets into GC-allocated
PlatformObjects. Their C++ wrapper classes are removed, and the LibJS
garbage collector is now responsible for their lifetimes.

There's a fair amount of hacks and band-aids in this patch, and we'll
have a lot of cleanup to do after this.

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

@@ -6,7 +6,6 @@
  */
 
 #include <LibWeb/Bindings/MainThreadVM.h>
-#include <LibWeb/Bindings/WindowObject.h>
 #include <LibWeb/DOM/Document.h>
 #include <LibWeb/HTML/PromiseRejectionEvent.h>
 #include <LibWeb/HTML/Scripting/Environments.h>
@@ -67,7 +66,7 @@ EventLoop& EnvironmentSettingsObject::responsible_event_loop()
 RunScriptDecision EnvironmentSettingsObject::can_run_script()
 {
     // 1. If the global object specified by settings is a Window object whose Document object is not fully active, then return "do not run".
-    if (is<Bindings::WindowObject>(global_object()) && !verify_cast<Bindings::WindowObject>(global_object()).impl().associated_document().is_fully_active())
+    if (is<HTML::Window>(global_object()) && !verify_cast<HTML::Window>(global_object()).associated_document().is_fully_active())
         return RunScriptDecision::DoNotRun;
 
     // 2. If scripting is disabled for settings, then return "do not run".
@@ -218,11 +217,11 @@ void EnvironmentSettingsObject::notify_about_rejected_promises(Badge<EventLoop>)
                 /* .reason = */ promise.result(),
             };
             // FIXME: This currently assumes that global is a WindowObject.
-            auto& window = verify_cast<Bindings::WindowObject>(*global.cell());
+            auto& window = verify_cast<HTML::Window>(*global.cell());
 
             auto promise_rejection_event = PromiseRejectionEvent::create(window, HTML::EventNames::unhandledrejection, event_init);
 
-            bool not_handled = window.impl().dispatch_event(*promise_rejection_event);
+            bool not_handled = window.dispatch_event(*promise_rejection_event);
 
             // 3. If notHandled is false, then the promise rejection is handled. Otherwise, the promise rejection is not handled.
 

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

@@ -62,7 +62,7 @@ struct EnvironmentSettingsObject
     // FIXME: A module map https://html.spec.whatwg.org/multipage/webappapis.html#concept-settings-object-module-map
 
     // https://html.spec.whatwg.org/multipage/webappapis.html#responsible-document
-    virtual RefPtr<DOM::Document> responsible_document() = 0;
+    virtual JS::GCPtr<DOM::Document> responsible_document() = 0;
 
     // https://html.spec.whatwg.org/multipage/webappapis.html#api-url-character-encoding
     virtual String api_url_character_encoding() = 0;

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

@@ -4,15 +4,15 @@
  * SPDX-License-Identifier: BSD-2-Clause
  */
 
-#include <LibWeb/Bindings/WindowObject.h>
 #include <LibWeb/DOM/Document.h>
 #include <LibWeb/HTML/Scripting/WindowEnvironmentSettingsObject.h>
+#include <LibWeb/HTML/Window.h>
 
 namespace Web::HTML {
 
 WindowEnvironmentSettingsObject::WindowEnvironmentSettingsObject(Window& window, NonnullOwnPtr<JS::ExecutionContext> execution_context)
     : EnvironmentSettingsObject(move(execution_context))
-    , m_window(window)
+    , m_window(JS::make_handle(window))
 {
 }
 
@@ -25,7 +25,7 @@ void WindowEnvironmentSettingsObject::setup(AK::URL const& creation_url, Nonnull
 
     // 2. Let window be realm's global object.
     // NOTE: We want to store the Window impl rather than the WindowObject.
-    auto& window = verify_cast<Bindings::WindowObject>(realm->global_object()).impl();
+    auto& window = verify_cast<HTML::Window>(realm->global_object()).impl();
 
     // 3. Let settings object be a new environment settings object whose algorithms are defined as follows:
     // NOTE: See the functions defined for this class.
@@ -61,7 +61,7 @@ void WindowEnvironmentSettingsObject::setup(AK::URL const& creation_url, Nonnull
 }
 
 // https://html.spec.whatwg.org/multipage/window-object.html#script-settings-for-window-objects:responsible-document
-RefPtr<DOM::Document> WindowEnvironmentSettingsObject::responsible_document()
+JS::GCPtr<DOM::Document> WindowEnvironmentSettingsObject::responsible_document()
 {
     // Return window's associated Document.
     return m_window->associated_document();

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

@@ -17,7 +17,7 @@ public:
 
     virtual ~WindowEnvironmentSettingsObject() override = default;
 
-    virtual RefPtr<DOM::Document> responsible_document() override;
+    virtual JS::GCPtr<DOM::Document> responsible_document() override;
     virtual String api_url_character_encoding() override;
     virtual AK::URL api_base_url() override;
     virtual Origin origin() override;
@@ -26,7 +26,7 @@ public:
 private:
     WindowEnvironmentSettingsObject(Window&, NonnullOwnPtr<JS::ExecutionContext>);
 
-    NonnullRefPtr<Window> m_window;
+    JS::Handle<Window> m_window;
 };
 
 }

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

@@ -20,7 +20,7 @@ class WorkerEnvironmentSettingsObject final
 public:
     WorkerEnvironmentSettingsObject(DOM::Document& document, NonnullOwnPtr<JS::ExecutionContext> execution_context)
         : EnvironmentSettingsObject(move(execution_context))
-        , m_document(document)
+        , m_document(JS::make_handle(document))
     {
     }
 
@@ -37,14 +37,14 @@ public:
 
     virtual ~WorkerEnvironmentSettingsObject() override = default;
 
-    RefPtr<DOM::Document> responsible_document() override { return m_document; }
+    JS::GCPtr<DOM::Document> responsible_document() override { return m_document.ptr(); }
     String api_url_character_encoding() override { return m_document->encoding_or_default(); }
     AK::URL api_base_url() override { return m_document->url(); }
     Origin origin() override { return m_document->origin(); }
     CanUseCrossOriginIsolatedAPIs cross_origin_isolated_capability() override { TODO(); }
 
 private:
-    NonnullRefPtr<DOM::Document> m_document;
+    JS::Handle<DOM::Document> m_document;
 };
 
 }