WebContent: Implement ConsoleGlobalObject which proxies to WindowObject

ConsoleGlobalObject is used as the global object when running javascript
from the Browser console. This lets us implement console-only functions
and variables (like `$0`) without exposing them to webpage content. It
passes other calls over to the usual WindowObject so any code that would
have worked in the webpage will still work in the console. :^)

Userland/Services/WebContent/ConsoleGlobalObject.cpp

@@ -0,0 +1,90 @@
+/*
+ * Copyright (c) 2021, Sam Atkins <atkinssj@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include "ConsoleGlobalObject.h"
+#include <LibWeb/Bindings/WindowObject.h>
+#include <LibWeb/DOM/Document.h>
+#include <LibWeb/DOM/Window.h>
+
+namespace WebContent {
+
+ConsoleGlobalObject::ConsoleGlobalObject(Web::Bindings::WindowObject& parent_object)
+    : m_window_object(&parent_object)
+{
+}
+
+ConsoleGlobalObject::~ConsoleGlobalObject()
+{
+}
+
+void ConsoleGlobalObject::visit_edges(Visitor& visitor)
+{
+    Base::visit_edges(visitor);
+    visitor.visit(m_window_object);
+}
+
+JS::Object* ConsoleGlobalObject::internal_get_prototype_of() const
+{
+    return m_window_object->internal_get_prototype_of();
+}
+
+bool ConsoleGlobalObject::internal_set_prototype_of(JS::Object* prototype)
+{
+    return m_window_object->internal_set_prototype_of(prototype);
+}
+
+bool ConsoleGlobalObject::internal_is_extensible() const
+{
+    return m_window_object->internal_is_extensible();
+}
+
+bool ConsoleGlobalObject::internal_prevent_extensions()
+{
+    return m_window_object->internal_prevent_extensions();
+}
+
+Optional<JS::PropertyDescriptor> ConsoleGlobalObject::internal_get_own_property(JS::PropertyName const& property_name) const
+{
+    if (auto result = m_window_object->internal_get_own_property(property_name); result.has_value())
+        return result;
+
+    return Base::internal_get_own_property(property_name);
+}
+
+bool ConsoleGlobalObject::internal_define_own_property(JS::PropertyName const& property_name, JS::PropertyDescriptor const& descriptor)
+{
+    return m_window_object->internal_define_own_property(property_name, descriptor);
+}
+
+bool ConsoleGlobalObject::internal_has_property(JS::PropertyName const& property_name) const
+{
+    return Object::internal_has_property(property_name) || m_window_object->internal_has_property(property_name);
+}
+
+JS::Value ConsoleGlobalObject::internal_get(JS::PropertyName const& property_name, JS::Value receiver) const
+{
+    if (m_window_object->has_own_property(property_name))
+        return m_window_object->internal_get(property_name, (receiver == this) ? m_window_object : receiver);
+
+    return Base::internal_get(property_name, receiver);
+}
+
+bool ConsoleGlobalObject::internal_set(JS::PropertyName const& property_name, JS::Value value, JS::Value receiver)
+{
+    return m_window_object->internal_set(property_name, value, (receiver == this) ? m_window_object : receiver);
+}
+
+bool ConsoleGlobalObject::internal_delete(JS::PropertyName const& property_name)
+{
+    return m_window_object->internal_delete(property_name);
+}
+
+JS::MarkedValueList ConsoleGlobalObject::internal_own_property_keys() const
+{
+    return m_window_object->internal_own_property_keys();
+}
+
+}