21534 [Android Text Input] Make the editing state listenable and allow batch edits  (affects: text input, cla: yes, platform-android, waiting for tree to go green)

21548 Extract the WindowInsetsAnimation.Callback subclass into a separate class that will be lazily loaded (cla: yes, platform-android, waiting for tree to go green)

21611 Preserve specified AssetResolvers when performing a hot restart or updating the asset directory (cla: yes, platform-android)

21665 Ensure JNI is not called from raster thread (cla: yes, platform-android, waiting for tree to go green)

21669 [flutter_releases] Flutter 1.22.1 Engine Cherrypicks (cla: yes, platform-android, platform-ios)