Merge "Offload initial headless app query to handler thread." into rvc-dev am: bcdd5c53 am: fcf71753

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/11708142

Change-Id: Ie06d8b35d3fa434a9204ce1233a42c7b0a85b4f4