Bug 915884 - Add tests for Inter-App Communication API (part 4, Gaia UI Marionette tests for APIs). r=squib r=ferjm
Merge pull request #17651 from airpingu/bug-915884-IAC-tests-part-4

Bug 915884 - Add tests for Inter-App Communication API (part 4, Gaia UI Marionette tests for APIs)