Agree w/Zac's concerns in https://bugzilla.mozilla.org/show_bug.cgi?id=948826#c14 - this is introducing a lot of unused code here. What we should do instead is add a test app that just focuses on the context of the problem here - device storage of each type of contacts. Think of the app being something like a simplified version of my permissions test app here - https://github.com/jds2501/webapi-permissions-tests/blob/gh-pages/test-webapi-permissions.zip.