Patch Set 1: I would prefer that you didn't submit this

(1 inline comment)

Looks good but can you please return 'this' in the setter?

Also, in your commit message, please add 

'Change-Id: Id9713a4849c772e030fca23dd64b993264f28366'

So when you amend your commit, Gerrit knows that it's this changeset to append the change too. It's in our contributor guide :)