Merge "profcollect: Register observers in a background thread" am: 75b0b6ee am: 565e1651 am: 97cd22b1 am: b03a8a2e am: aae6dc80

Original change: https://android-review.googlesource.com/c/platform/frameworks/base/+/2017976

Change-Id: I5271afd78b544a25cc0b114aace4549fdb506595