Add project files.

tests/editor_headless/stubs/imgui_stdlib.h

@@ -0,0 +1,7 @@
+#pragma once
+#include <string>
+#include "imgui.h"
+namespace ImGui {
+bool InputText(const char *label, std::string *str, ImGuiInputTextFlags flags = 0, ImGuiInputTextCallback callback = nullptr, void *user_data = nullptr);
+bool InputTextWithHint(const char *label, const char *hint, std::string *str, ImGuiInputTextFlags flags = 0, ImGuiInputTextCallback callback = nullptr, void *user_data = nullptr);
+}