Allowed closing boxes and layers with mouse back button.

Telegram/SourceFiles/window/window_controller.cpp

@@ -463,6 +463,10 @@ void Controller::hideSettingsAndLayer(anim::type animated) {
 	_widget.ui_hideSettingsAndLayer(animated);
 }
 
+bool Controller::closeLayerByBackButton() {
+	return _widget.closeLayerByBackButton();
+}
+
 bool Controller::isLayerShown() const {
 	return _widget.ui_isLayerShown();
 }