LibWeb: Use JS::SafeFunction in the HTML task queues

This means that HTML tasks automatically protect anything in their
capture lists, and we no longer need to jump through hoops with
JS::Handle etc.

Userland/Libraries/LibWeb/HTML/EventLoop/EventLoop.cpp

@@ -231,13 +231,13 @@ void EventLoop::process()
 
 // FIXME: This is here to paper over an issue in the HTML parser where it'll create new interpreters (and thus ESOs) on temporary documents created for innerHTML if it uses Document::realm() to get the global object.
 //        Use queue_global_task instead.
-void old_queue_global_task_with_document(HTML::Task::Source source, DOM::Document& document, Function<void()> steps)
+void old_queue_global_task_with_document(HTML::Task::Source source, DOM::Document& document, JS::SafeFunction<void()> steps)
 {
     main_thread_event_loop().task_queue().add(HTML::Task::create(source, &document, move(steps)));
 }
 
 // https://html.spec.whatwg.org/multipage/webappapis.html#queue-a-global-task
-void queue_global_task(HTML::Task::Source source, JS::Object& global_object, Function<void()> steps)
+void queue_global_task(HTML::Task::Source source, JS::Object& global_object, JS::SafeFunction<void()> steps)
 {
     // 1. Let event loop be global's relevant agent's event loop.
     auto& global_custom_data = verify_cast<Bindings::WebEngineCustomData>(*global_object.vm().custom_data());
@@ -255,7 +255,7 @@ void queue_global_task(HTML::Task::Source source, JS::Object& global_object, Fun
 }
 
 // https://html.spec.whatwg.org/#queue-a-microtask
-void queue_a_microtask(DOM::Document* document, Function<void()> steps)
+void queue_a_microtask(DOM::Document* document, JS::SafeFunction<void()> steps)
 {
     // 1. If event loop was not given, set event loop to the implied event loop.
     auto& event_loop = HTML::main_thread_event_loop();

Userland/Libraries/LibWeb/HTML/EventLoop/EventLoop.h

@@ -10,6 +10,7 @@
 #include <AK/WeakPtr.h>
 #include <LibCore/Forward.h>
 #include <LibJS/Forward.h>
+#include <LibJS/SafeFunction.h>
 #include <LibWeb/HTML/EventLoop/TaskQueue.h>
 
 namespace Web::HTML {
@@ -107,9 +108,9 @@ private:
 };
 
 EventLoop& main_thread_event_loop();
-void old_queue_global_task_with_document(HTML::Task::Source, DOM::Document&, Function<void()> steps);
-void queue_global_task(HTML::Task::Source, JS::Object&, Function<void()> steps);
-void queue_a_microtask(DOM::Document*, Function<void()> steps);
+void old_queue_global_task_with_document(HTML::Task::Source, DOM::Document&, JS::SafeFunction<void()> steps);
+void queue_global_task(HTML::Task::Source, JS::Object&, JS::SafeFunction<void()> steps);
+void queue_a_microtask(DOM::Document*, JS::SafeFunction<void()> steps);
 void perform_a_microtask_checkpoint();
 
 }

Userland/Libraries/LibWeb/HTML/EventLoop/Task.cpp

@@ -9,7 +9,7 @@
 
 namespace Web::HTML {
 
-Task::Task(Source source, DOM::Document* document, Function<void()> steps)
+Task::Task(Source source, DOM::Document* document, JS::SafeFunction<void()> steps)
     : m_source(source)
     , m_steps(move(steps))
     , m_document(JS::make_handle(document))

Userland/Libraries/LibWeb/HTML/EventLoop/Task.h

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021, Andreas Kling <kling@serenityos.org>
+ * Copyright (c) 2021-2022, Andreas Kling <kling@serenityos.org>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -10,6 +10,7 @@
 #include <AK/NonnullOwnPtr.h>
 #include <AK/RefPtr.h>
 #include <LibJS/Heap/Handle.h>
+#include <LibJS/SafeFunction.h>
 #include <LibWeb/Forward.h>
 
 namespace Web::HTML {
@@ -30,7 +31,7 @@ public:
         JavaScriptEngine,
     };
 
-    static NonnullOwnPtr<Task> create(Source source, DOM::Document* document, Function<void()> steps)
+    static NonnullOwnPtr<Task> create(Source source, DOM::Document* document, JS::SafeFunction<void()> steps)
     {
         return adopt_own(*new Task(source, document, move(steps)));
     }
@@ -45,10 +46,10 @@ public:
     bool is_runnable() const;
 
 private:
-    Task(Source, DOM::Document*, Function<void()> steps);
+    Task(Source, DOM::Document*, JS::SafeFunction<void()> steps);
 
     Source m_source { Source::Unspecified };
-    Function<void()> m_steps;
+    JS::SafeFunction<void()> m_steps;
     JS::Handle<DOM::Document> m_document;
 };