Store mHistoricTimes as longs intead of floats am: 31ef24c934 am: 1802dc3466 am: 27b9abc973

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

Change-Id: I66bbada4462f3186ed6398ab3d89e8ceccb34e02