Internal: b/242216228

Use case

Several popular pub packages (local_auth, health) require the use of FlutterFragmentActivity in apps. Apps that use those packages should be able to support predictive back, too.

Proposal

Predictive back support was added to FlutterActivity in flutter/engine#52302 and to FlutterFragment in flutter/engine#52302. Support should also be added to FlutterFragmentActivity, including support for route transitions (flutter/engine#49093).

What is predictive back?

What are predictive back route transitions?