Starting with Android 5, WebView is implemented on top of a different rendering engine -and the Android docs talk about what has changed-, but WebView will continue to be fully supported (including getting fixes through the Play Store).
Whew! I'm glad it wasn't deprecated because I just added some coverage of it to the second (current) edition of my book. I tested it on several different versions of Android, including Android 6, and it worked fine. Thanks!