Bug 997064: Do not call navigator.mozFMRadio from system r=baku a=1.3t+

From 6d34051ae4e63d90f62ca89ae50f1bf8fd26580e Mon Sep 17 00:00:00 2001
 app.
---
 dom/fmradio/FMRadioService.cpp                |   63 +++++++++++++------------
 dom/fmradio/FMRadioService.h                  |    6 +--
 dom/fmradio/test/marionette/test_bug876597.js |    6 +--
 3 files changed, 38 insertions(+), 37 deletions(-)