Bug 828222 - [Sound] Sound playback is delayed giving the impression the device has poor performance.

Do the Keyboard highlight DOM-operations _after_ the audio feedback

Signed-off-by: Rick Waldron <waldron.rick@gmail.com>
Merge pull request #8176 from rwldrn/828222

Bug 828222 - [Sound] Sound playback is delayed perceived poor performance. r=djf