LibWeb: Implement ModuleScript and JavaScriptModuleScript

This patchs adds the Web::HTML::Script subclass ModuleScript and
JavaScriptModuleScript as a type of ModuleScript as well as various
algorithms related to JavaScript module scripts.

Co-authored-by: davidot <davidot@serenityos.org>

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

@@ -0,0 +1,58 @@
+/*
+ * Copyright (c) 2022, networkException <networkexception@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <LibJS/SourceTextModule.h>
+#include <LibWeb/HTML/Scripting/ModuleMap.h>
+#include <LibWeb/HTML/Scripting/Script.h>
+
+namespace Web::HTML {
+
+// https://html.spec.whatwg.org/multipage/webappapis.html#module-script
+class ModuleScript : public Script {
+    JS_CELL(ModuleScript, Script);
+
+public:
+    virtual ~ModuleScript() override;
+
+protected:
+    ModuleScript(AK::URL base_url, String filename, EnvironmentSettingsObject& environment_settings_object);
+};
+
+class JavaScriptModuleScript final : public ModuleScript {
+    JS_CELL(JavaScriptModuleScript, ModuleScript);
+
+public:
+    virtual ~JavaScriptModuleScript() override;
+
+    static JS::GCPtr<JavaScriptModuleScript> create(String const& filename, StringView source, EnvironmentSettingsObject&, AK::URL base_url);
+
+    enum class PreventErrorReporting {
+        Yes,
+        No
+    };
+
+    JS::Promise* run(PreventErrorReporting = PreventErrorReporting::No);
+
+    JS::SourceTextModule const* record() const { return m_record.ptr(); };
+    JS::SourceTextModule* record() { return m_record.ptr(); };
+
+protected:
+    JavaScriptModuleScript(AK::URL base_url, String filename, EnvironmentSettingsObject& environment_settings_object);
+
+private:
+    virtual void visit_edges(JS::Cell::Visitor&) override;
+
+    JS::GCPtr<JS::SourceTextModule> m_record;
+
+    size_t m_fetch_internal_request_count { 0 };
+    size_t m_completed_fetch_internal_request_count { 0 };
+
+    Function<void(JavaScriptModuleScript const*)> m_completed_fetch_internal_callback;
+};
+
+}