WebContent: Add $() and $$() functions to browser console

These are based on the ones in Firefox:

`$(selector, element = document)`:
    Equivalent to `element.querySelector(selector)`.

`$$(selector, element = document)`:
    Equivalent to `element.querySelectorAll(selector)`.

Userland/Services/WebContent/ConsoleGlobalObject.cpp

@@ -5,8 +5,11 @@
  */
 
 #include "ConsoleGlobalObject.h"
+#include <LibJS/Runtime/Array.h>
 #include <LibJS/Runtime/Completion.h>
+#include <LibWeb/Bindings/ExceptionOrUtils.h>
 #include <LibWeb/DOM/Document.h>
+#include <LibWeb/DOM/NodeList.h>
 #include <LibWeb/HTML/Window.h>
 
 namespace WebContent {
@@ -23,6 +26,8 @@ void ConsoleGlobalObject::initialize(JS::Realm& realm)
 
     define_native_accessor(realm, "$0", $0_getter, nullptr, 0);
     define_native_accessor(realm, "$_", $__getter, nullptr, 0);
+    define_native_function(realm, "$", $_function, 2, JS::default_attributes);
+    define_native_function(realm, "$$", $$_function, 2, JS::default_attributes);
 }
 
 void ConsoleGlobalObject::visit_edges(Visitor& visitor)
@@ -117,4 +122,58 @@ JS_DEFINE_NATIVE_FUNCTION(ConsoleGlobalObject::$__getter)
     return console_global_object->m_most_recent_result;
 }
 
+JS_DEFINE_NATIVE_FUNCTION(ConsoleGlobalObject::$_function)
+{
+    auto* console_global_object = TRY(get_console(vm));
+    auto& window = *console_global_object->m_window_object;
+
+    auto selector = TRY(vm.argument(0).to_string(vm));
+
+    if (vm.argument_count() > 1) {
+        auto element_value = vm.argument(1);
+        if (!(element_value.is_object() && is<Web::DOM::ParentNode>(element_value.as_object()))) {
+            return vm.throw_completion<JS::TypeError>(JS::ErrorType::NotAnObjectOfType, "Node");
+        }
+
+        auto& element = static_cast<Web::DOM::ParentNode&>(element_value.as_object());
+        return TRY(Web::Bindings::throw_dom_exception_if_needed(vm, [&]() {
+            return element.query_selector(selector);
+        }));
+    }
+
+    return TRY(Web::Bindings::throw_dom_exception_if_needed(vm, [&]() {
+        return window.associated_document().query_selector(selector);
+    }));
+}
+
+JS_DEFINE_NATIVE_FUNCTION(ConsoleGlobalObject::$$_function)
+{
+    auto* console_global_object = TRY(get_console(vm));
+    auto& window = *console_global_object->m_window_object;
+
+    auto selector = TRY(vm.argument(0).to_string(vm));
+
+    Web::DOM::ParentNode* element = &window.associated_document();
+
+    if (vm.argument_count() > 1) {
+        auto element_value = vm.argument(1);
+        if (!(element_value.is_object() && is<Web::DOM::ParentNode>(element_value.as_object()))) {
+            return vm.throw_completion<JS::TypeError>(JS::ErrorType::NotAnObjectOfType, "Node");
+        }
+
+        element = static_cast<Web::DOM::ParentNode*>(&element_value.as_object());
+    }
+
+    auto node_list = TRY(Web::Bindings::throw_dom_exception_if_needed(vm, [&]() {
+        return element->query_selector_all(selector);
+    }));
+
+    auto* array = TRY(JS::Array::create(*vm.current_realm(), node_list->length()));
+    for (auto i = 0u; i < node_list->length(); ++i) {
+        TRY(array->create_data_property_or_throw(i, node_list->item_value(i)));
+    }
+
+    return array;
+}
+
 }

Userland/Services/WebContent/ConsoleGlobalObject.h

@@ -42,6 +42,10 @@ private:
     JS_DECLARE_NATIVE_FUNCTION($0_getter);
     // $_, the value of the most recent expression entered into the console
     JS_DECLARE_NATIVE_FUNCTION($__getter);
+    // $(selector, element), equivalent to `(element || document).querySelector(selector)`
+    JS_DECLARE_NATIVE_FUNCTION($_function);
+    // $$(selector, element), equivalent to `(element || document).querySelectorAll(selector)`
+    JS_DECLARE_NATIVE_FUNCTION($$_function);
 
     Web::HTML::Window* m_window_object;
     JS::Value m_most_recent_result { JS::js_undefined() };