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.

1 files changed, 18 insertions, 22 deletions

diff --git a/Userland/Libraries/LibWeb/DOM/TreeWalker.h b/Userland/Libraries/LibWeb/DOM/TreeWalker.h
index 076c6511aa..e43f7c21f2 100644
--- a/Userland/Libraries/LibWeb/DOM/TreeWalker.h
+++ b/Userland/Libraries/LibWeb/DOM/TreeWalker.h
@@ -12,61 +12,60 @@ namespace Web::DOM {
 
 // https://dom.spec.whatwg.org/#treewalker
 class TreeWalker final : public Bindings::PlatformObject {
-    JS_OBJECT(TreeWalker, JS::Object);
+    WEB_PLATFORM_OBJECT(TreeWalker, JS::Object);
 
 public:
     static JS::NonnullGCPtr<TreeWalker> create(Node& root, unsigned what_to_show, JS::GCPtr<NodeFilter>);
 
-    explicit TreeWalker(Node& root);
     virtual ~TreeWalker() override;
 
-    TreeWalker& impl() { return *this; }
-
-    NonnullRefPtr<Node> current_node() const;
+    JS::NonnullGCPtr<Node> current_node() const;
     void set_current_node(Node&);
 
-    JS::ThrowCompletionOr<RefPtr<Node>> parent_node();
-    JS::ThrowCompletionOr<RefPtr<Node>> first_child();
-    JS::ThrowCompletionOr<RefPtr<Node>> last_child();
-    JS::ThrowCompletionOr<RefPtr<Node>> previous_sibling();
-    JS::ThrowCompletionOr<RefPtr<Node>> next_sibling();
-    JS::ThrowCompletionOr<RefPtr<Node>> previous_node();
-    JS::ThrowCompletionOr<RefPtr<Node>> next_node();
+    JS::ThrowCompletionOr<JS::GCPtr<Node>> parent_node();
+    JS::ThrowCompletionOr<JS::GCPtr<Node>> first_child();
+    JS::ThrowCompletionOr<JS::GCPtr<Node>> last_child();
+    JS::ThrowCompletionOr<JS::GCPtr<Node>> previous_sibling();
+    JS::ThrowCompletionOr<JS::GCPtr<Node>> next_sibling();
+    JS::ThrowCompletionOr<JS::GCPtr<Node>> previous_node();
+    JS::ThrowCompletionOr<JS::GCPtr<Node>> next_node();
 
-    NonnullRefPtr<Node> root() { return m_root; }
+    JS::NonnullGCPtr<Node> root() { return m_root; }
 
     NodeFilter* filter() { return m_filter.ptr(); }
 
     unsigned what_to_show() const { return m_what_to_show; }
 
 private:
+    explicit TreeWalker(Node& root);
+
     virtual void visit_edges(Cell::Visitor&) override;
 
     enum class ChildTraversalType {
         First,
         Last,
     };
-    JS::ThrowCompletionOr<RefPtr<Node>> traverse_children(ChildTraversalType);
+    JS::ThrowCompletionOr<JS::GCPtr<Node>> traverse_children(ChildTraversalType);
 
     enum class SiblingTraversalType {
         Next,
         Previous,
     };
-    JS::ThrowCompletionOr<RefPtr<Node>> traverse_siblings(SiblingTraversalType);
+    JS::ThrowCompletionOr<JS::GCPtr<Node>> traverse_siblings(SiblingTraversalType);
 
     JS::ThrowCompletionOr<NodeFilter::Result> filter(Node&);
 
     // https://dom.spec.whatwg.org/#concept-traversal-root
-    NonnullRefPtr<DOM::Node> m_root;
+    JS::NonnullGCPtr<Node> m_root;
 
     // https://dom.spec.whatwg.org/#treewalker-current
-    NonnullRefPtr<DOM::Node> m_current;
+    JS::NonnullGCPtr<Node> m_current;
 
     // https://dom.spec.whatwg.org/#concept-traversal-whattoshow
     unsigned m_what_to_show { 0 };
 
     // https://dom.spec.whatwg.org/#concept-traversal-filter
-    JS::GCPtr<DOM::NodeFilter> m_filter;
+    JS::GCPtr<NodeFilter> m_filter;
 
     // https://dom.spec.whatwg.org/#concept-traversal-active
     bool m_active { false };
@@ -74,7 +73,4 @@ private:
 
 }
 
-namespace Web::Bindings {
-inline JS::Object* wrap(JS::Realm&, Web::DOM::TreeWalker& object) { return &object; }
-using TreeWalkerWrapper = Web::DOM::TreeWalker;
-}
+WRAPPER_HACK(TreeWalker, Web::DOM)