Defer speed-dial web commands off the webview callback stack

src/slic3r/GUI/SpeedDialDialog.hpp

@@ -3,6 +3,8 @@
 
 #include <slic3r/GUI/Widgets/WebViewHostDialog.hpp>
 #include <nlohmann/json_fwd.hpp>
+#include <atomic>
+#include <memory>
 #include <string>
 
 namespace Slic3r { namespace GUI {
@@ -11,15 +13,20 @@ class SpeedDialWebDialog : public WebViewHostDialog
 {
 public:
     explicit SpeedDialWebDialog(wxWindow* parent);
+    ~SpeedDialWebDialog() override;
     void request_show();
 
 private:
     void on_script_message(const nlohmann::json& payload) override;
+    void handle_web_command(const nlohmann::json& payload);
     void resize_to_content(int height);
     void run_action(const std::string& id, const std::string& title);
     void send_actions();
 
     bool m_page_ready{false};
+    // Guards the CallAfter in on_script_message across dialog destruction, same as
+    // PluginsDialog::m_alive (PluginsDialog.hpp:249).
+    std::shared_ptr<std::atomic<bool>> m_alive = std::make_shared<std::atomic<bool>>(true);
 };
 
 }}