Bug 901587 - Remove mouse_event_shim from fm radio
Merge pull request #11355 from KevinGrandon/bug_901587_remove_mouse_events_fm

Bug 901587 - Remove mouse_event_shim from fm radio r=timdream
Test tests
Add more tests
Add more integration tests
Lazily retrieve element references

Using ES5 accessor methods allows the element lookup table to be defined
up-front, but defers access of elements until they are present in the
application.
Add more tests