Function capability_granting_ipc 

pub fn capability_granting_ipc(
    doc: &str,
    webview_label: &str,
    window_label: &str,
) -> Result<Option<String>, DevToolsError>

The identifier of the first capability in doc that applies to the webview and grants permissions. A capability applies when one of its webviews patterns matches the webview label or one of its windows patterns matches the label of the window that hosts the webview. webview_label may be a content prefix pattern (html-content-*); overlap is judged conservatively.