LibWeb: Add partially functioning Worker API

Add a partial implementation of HTML5 Worker API.
Messages can be sent from the inner context externally.

Userland/Libraries/LibWeb/HTML/WorkerDebugConsoleClient.h

@@ -0,0 +1,32 @@
+/*
+ * Copyright (c) 2022, Ben Abraham <ben.d.abraham@gmail.com>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/RefCounted.h>
+#include <AK/Weakable.h>
+#include <LibJS/Console.h>
+
+namespace Web::HTML {
+
+// NOTE: Temporary class to handle console messages from inside Workers
+
+class WorkerDebugConsoleClient final
+    : public JS::ConsoleClient
+    , public RefCounted<WorkerDebugConsoleClient>
+    , public Weakable<WorkerDebugConsoleClient> {
+public:
+    WorkerDebugConsoleClient(JS::Console& console);
+
+    virtual void clear() override;
+    virtual void end_group() override;
+    virtual JS::ThrowCompletionOr<JS::Value> printer(JS::Console::LogLevel log_level, PrinterArguments arguments) override;
+
+private:
+    int m_group_stack_depth { 0 };
+};
+
+} // namespace Web::HTML