LibJS+LibWeb: Use GC::Weak instead of AK::WeakPtr for GC-allocated types

This makes some common types like JS::Object smaller (by 8 bytes) and
yields a minor speed improvement on many benchmarks.

Libraries/LibWeb/HTML/EventLoop/EventLoop.h

@@ -8,9 +8,9 @@
 
 #include <AK/Function.h>
 #include <AK/Noncopyable.h>
-#include <AK/WeakPtr.h>
 #include <LibCore/Forward.h>
 #include <LibGC/Ptr.h>
+#include <LibGC/Weak.h>
 #include <LibJS/Forward.h>
 #include <LibWeb/Export.h>
 #include <LibWeb/HTML/EventLoop/TaskQueue.h>
@@ -119,7 +119,7 @@ private:
     // https://html.spec.whatwg.org/multipage/webappapis.html#performing-a-microtask-checkpoint
     bool m_performing_a_microtask_checkpoint { false };
 
-    Vector<WeakPtr<DOM::Document>> m_documents;
+    Vector<GC::Weak<DOM::Document>> m_documents;
 
     // Used to implement step 4 of "perform a microtask checkpoint".
     // NOTE: These are weak references! ESO registers and unregisters itself from the event loop manually.

Libraries/LibWeb/HTML/FormAssociatedElement.h

@@ -8,7 +8,7 @@
 #pragma once
 
 #include <AK/String.h>
-#include <AK/WeakPtr.h>
+#include <LibGC/Weak.h>
 #include <LibWeb/Bindings/HTMLFormElementPrototype.h>
 #include <LibWeb/DOM/InputEventsTarget.h>
 #include <LibWeb/Export.h>
@@ -178,7 +178,7 @@ protected:
 private:
     void reset_form_owner();
 
-    WeakPtr<HTMLFormElement> m_form;
+    GC::Weak<HTMLFormElement> m_form;
 
     // https://html.spec.whatwg.org/multipage/form-control-infrastructure.html#parser-inserted-flag
     bool m_parser_inserted { false };

Libraries/LibWeb/HTML/HTMLInputElement.cpp

@@ -380,7 +380,7 @@ static void show_the_picker_if_applicable(HTMLInputElement& element)
             // 2. Wait for the user to have made their selection.
             auto accepted_file_types = element.parse_accept_attribute();
             auto allow_multiple_files = element.has_attribute(HTML::AttributeNames::multiple) ? AllowMultipleFiles::Yes : AllowMultipleFiles::No;
-            auto weak_element = element.make_weak_ptr<HTMLInputElement>();
+            auto weak_element = GC::Weak<HTMLInputElement> { element };
 
             element.set_is_open(true);
             element.document().browsing_context()->top_level_browsing_context()->page().did_request_file_picker(weak_element, accepted_file_types, allow_multiple_files);
@@ -404,7 +404,7 @@ static void show_the_picker_if_applicable(HTMLInputElement& element)
     //    events, or a cancel event.)
     else {
         if (element.type_state() == HTMLInputElement::TypeAttributeState::Color) {
-            auto weak_element = element.make_weak_ptr<HTMLInputElement>();
+            auto weak_element = GC::Weak<HTMLInputElement> { element };
             element.set_is_open(true);
             element.document().browsing_context()->top_level_browsing_context()->page().did_request_color_picker(weak_element, Color::from_utf16_string(element.value()).value_or(Color(0, 0, 0)));
         }

Libraries/LibWeb/HTML/HTMLLinkElement.cpp

@@ -570,7 +570,7 @@ bool HTMLLinkElement::stylesheet_linked_resource_fetch_setup_steps(Fetch::Infras
 
 void HTMLLinkElement::set_parser_document(Badge<HTMLParser>, GC::Ref<DOM::Document> document)
 {
-    m_parser_document = document->make_weak_ptr<DOM::Document>();
+    m_parser_document = document;
 }
 
 bool HTMLLinkElement::is_implicitly_potentially_render_blocking() const

Libraries/LibWeb/HTML/HTMLLinkElement.h

@@ -167,7 +167,7 @@ private:
 
     Optional<String> m_mime_type;
 
-    WeakPtr<DOM::Document> m_parser_document;
+    GC::Weak<DOM::Document> m_parser_document;
 };
 
 }

Libraries/LibWeb/HTML/HTMLSelectElement.cpp

@@ -480,7 +480,7 @@ void HTMLSelectElement::show_the_picker_if_applicable()
     }
 
     // Request select dropdown
-    auto weak_element = make_weak_ptr<HTMLSelectElement>();
+    auto weak_element = GC::Weak<HTMLSelectElement> { *this };
     auto rect = get_bounding_client_rect();
     auto position = document().navigable()->to_top_level_position(Web::CSSPixelPoint { rect.x(), rect.bottom() });
     document().page().did_request_select_dropdown(weak_element, position, rect.width(), m_select_items);

Libraries/LibWeb/HTML/HTMLTextAreaElement.cpp

@@ -31,10 +31,10 @@ GC_DEFINE_ALLOCATOR(HTMLTextAreaElement);
 
 HTMLTextAreaElement::HTMLTextAreaElement(DOM::Document& document, DOM::QualifiedName qualified_name)
     : HTMLElement(document, move(qualified_name))
-    , m_input_event_timer(Core::Timer::create_single_shot(0, [weak_this = make_weak_ptr()]() {
+    , m_input_event_timer(Core::Timer::create_single_shot(0, [weak_this = GC::Weak<HTMLTextAreaElement> { *this }]() {
         if (!weak_this)
             return;
-        static_cast<HTMLTextAreaElement*>(weak_this.ptr())->queue_firing_input_event();
+        weak_this->queue_firing_input_event();
     }))
 {
 }

Libraries/LibWeb/HTML/Navigable.h

@@ -51,8 +51,7 @@ struct PaintConfig {
 };
 
 // https://html.spec.whatwg.org/multipage/document-sequences.html#navigable
-class WEB_API Navigable : public JS::Cell
-    , public Weakable<Navigable> {
+class WEB_API Navigable : public JS::Cell {
     GC_CELL(Navigable, JS::Cell);
     GC_DECLARE_ALLOCATOR(Navigable);