Merge "Use elapsed time as timestamp of activity launch" into sc-dev am:...

Merge "Use elapsed time as timestamp of activity launch" into sc-dev am: f192f080 am: c4569c5c am: aa201f63

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/14419582

Change-Id: Ic36ccb04afef37a71da1d582bce32ba5363a85d6