HackStudio: Add evaluate expression popup to debugger

This implements a dialog that can be used to evaluate a JS expression
in the HackStudio's Debugger context. It also implements simple
C++ Variable <-> JS Value conversion, allowing for JS expressions
to read/write variables in the debugger scope.

Currently, C++ structs are mapped to JS objects by way of a JS proxy,
however this leads to issues when printing, so this will be changed
in a later commit.

Userland/DevTools/HackStudio/Debugger/EvaluateExpressionDialog.h

@@ -0,0 +1,33 @@
+/*
+ * Copyright (c) 2021, Hunter Salyer <thefalsehonesty@gmail.com>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <LibGUI/Dialog.h>
+#include <LibWeb/InProcessWebView.h>
+
+namespace HackStudio {
+
+class EvaluateExpressionDialog : public GUI::Dialog {
+    C_OBJECT(EvaluateExpressionDialog);
+
+public:
+    explicit EvaluateExpressionDialog(Window* parent_window);
+
+private:
+    void build(Window* parent_window);
+    void handle_evaluation(const String& expression);
+    void set_output(const StringView& html);
+
+    NonnullOwnPtr<JS::Interpreter> m_interpreter;
+    RefPtr<GUI::TextBox> m_text_editor;
+    RefPtr<Web::InProcessWebView> m_output_view;
+    RefPtr<Web::DOM::Element> m_output_container;
+    RefPtr<GUI::Button> m_evaluate_button;
+    RefPtr<GUI::Button> m_close_button;
+};
+
+}