Merge "Port IME tasksnapshot over to shell transitions" into sc-v2-dev am: 4097e44f2a am: f81ed8bf60

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/15819924

Change-Id: I8a310787dc1d03bfd57d3fd60ff7d8da33260186