Make Ethernet interfaces more testable. am: fb800f0d88 am: 372bbdb61e

Change-Id: I437fe3a5462d64a20675642264fc0742469bebd2
tree: 67408f1a62dc8c5f866332f00d0c4ea78f2e6463
  1. java/
  2. tests/
  3. .gitignore
  4. Android.bp