From what I can tell, the compatibility plan is to market flutter/dart as a cross-platform development toolkit for Android and iOS.
Fuchsia won't run android apps, but fuchsia apps will run on Android and iOS.
Fuchsia won't run android apps, but fuchsia apps will run on Android and iOS.
Chrome OS already runs Android, so it would be a matter of stitching the Chrome os shell into Fuchsia to have both running in Fuchsia. First with virtualization of Linux, and later without it.
[1] https://9to5google.com/2018/04/26/fuchsia-android-runtime-ap...