Changes to make eth service methods more testable am: 1daccdcb49 am: 40a6d9a719

Original change: https://android-review.googlesource.com/c/platform/frameworks/opt/net/ethernet/+/1934759

Change-Id: I747b401718c4860f6f38d925cf6b050fb7957470
tree: 28e16901b342bb8c705e250ea82ada7e687d0dc8
  1. service-t/
  2. tests/