Google Advertising ID is not accessible to progressive web app running in browser and so the installed PWA.
Said that, you can make it available to your installed PWA using an Android service(which is a native code getting the Google Advertising ID) and passing it to your PWA using Deep links, by setting a Indent filter to your PWA with a URL and have the ID retrieved in your native code passed to web app in the query para (URL).
You can refer to this java code to retrieve device identifiers and wrap it as a Android service, which calls your PWA using deep links.
与恶龙缠斗过久,自身亦成为恶龙；凝视深渊过久,深渊将回以凝视…
