Improve settings button selection handling

Will now try to keep the current button selection if possible.
This can be useful when switching between source of the same time.

plugins/base/utils/source-properties-button.hpp

@@ -1,12 +1,16 @@
 #pragma once
+#include "filter-combo-box.hpp"
+
 #include <obs.hpp>
-#include <QComboBox>
 #include <qmetatype.h>
 #include <string>
 #include <vector>
 
 namespace advss {
 
+class SourceSelection;
+class FilterSelection;
+
 struct SourceSettingButton {
 	bool Save(obs_data_t *obj) const;
 	bool Load(obs_data_t *obj);
@@ -18,7 +22,23 @@ struct SourceSettingButton {
 
 std::vector<SourceSettingButton> GetSourceButtons(OBSWeakSource source);
 void PressSourceButton(const SourceSettingButton &button, obs_source_t *source);
-void PopulateSourceButtonSelection(QComboBox *list, OBSWeakSource source);
+
+class SourceSettingsButtonSelection : public FilterComboBox {
+	Q_OBJECT
+
+public:
+	SourceSettingsButtonSelection(QWidget *parent = nullptr);
+	void SetSource(const OBSWeakSource &source,
+		       bool restorePreviousSelection = true);
+	void SetSelection(const OBSWeakSource &source,
+			  const SourceSettingButton &button);
+
+signals:
+	void SelectionChanged(const SourceSettingButton &);
+
+private:
+	void PopulateSelection(const OBSWeakSource &source);
+};
 
 } // namespace advss