Store mHistoricTimes as longs intead of floats am: 31ef24c934 am: 94dbcefe2a am: a838d9ebfe

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/apps/Launcher3/+/12375534

Change-Id: I4f63d9d27438dd44e853299121d426de715ab66c