Qt: Move speed settings into its own category

src/duckstation-qt/emulationsettingswidget.h

@@ -0,0 +1,28 @@
+#pragma once
+
+#include <QtWidgets/QWidget>
+
+#include "ui_emulationsettingswidget.h"
+
+class QtHostInterface;
+class SettingsDialog;
+
+class EmulationSettingsWidget : public QWidget
+{
+  Q_OBJECT
+
+public:
+  explicit EmulationSettingsWidget(QtHostInterface* host_interface, QWidget* parent, SettingsDialog* dialog);
+  ~EmulationSettingsWidget();
+
+private Q_SLOTS:
+  void onEmulationSpeedIndexChanged(int index);
+  void onFastForwardSpeedIndexChanged(int index);
+  void onTurboSpeedIndexChanged(int index);
+
+private:
+
+  Ui::EmulationSettingsWidget m_ui;
+
+  QtHostInterface* m_host_interface;
+};