Add real to elapsed offset to shell transition trace am: 541c4b60 am: eb290ffb

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/22988307



Change-Id: I3018f0c21ed0cabc4544148079d2fac0155ff091
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>