This feature allows autofill to look into ShadowDOM when collecting form controls within a form element. With the adoption of web components, it is common to wrap form controls like input elements in ShadowDOM. When autofill traverses the children of form elements to collect form controls, it currently skips ShadowDOM, and makes these form controls never get autofilled. This feature will make autofill also traverse into ShadowDOM when collecting form controls.