Update the Launch Handler implementation to ensure LaunchParams.targetURL is populated when a PWA is launched via File Handling. Previously, this property was null when a file launch was directed to an existing window. This change ensures that the URL from the developer's manifest "action" field (the same url the document is required to be currently loading) is available to the launchQueue consumer.
This change aligns Chromium’s implementation with the Web App Launch specification and provides consistency across different launch triggers. Currently, shortcut launches and navigation capturing launches populate the targetURL, but 'file handling' launches did not. Providing the URL context allows developers to better understand the intent of the launch or handle specific routing logic even when the primary payload is a set of file handles. See: https://crbug.com/464314997, https://github.com/WICG/web-app-launch/issues/97
Samples: https://googlechrome.github.io/samples/pwa-testing/principled-ring-yarrow