setDefaultVariantId(mPropertyBag) {
			setAdaptationIdInPropertyBag(mPropertyBag);
			return setReferenceAndPersistencyKeyInPropertyBagAndCallFunction(mPropertyBag, CompVariantState.setDefault);
		}
Sets the default variant for the current control synchronously.
A new change object is created or an existing change is updated. This change object is kept in memory and can be flushed using save.
WARNING: The consumer has to make sure that the changes have already been retrieved with <code>getChanges</code>.

@param {object} mPropertyBag - Object with parameters as properties
@param {sap.ui.comp.smartvariants.SmartVariantManagement|
			sap.ui.comp.smartfilterbar.SmartFilterBar|
			sap.ui.comp.smarttable.SmartTable|
			sap.ui.comp.smartchart.SmartChart} mPropertyBag.control - Variant management control for which a variant should be set as 'Default'
@param {string} mPropertyBag.defaultVariantId - ID of the new default variant
@param {string} [mPropertyBag.generator] - ID for the creating class / use case of the setDefault
@param {string} [mPropertyBag.compositeCommand] - Name of the composite command triggering the setting of the default
@param {sap.ui.fl.Layer} [mPropertyBag.layer = Layer.USER] - Enables setDefault for the given layer
@returns {object} Default variant change
@private
@ui5-restricted