Since we converted MediaDescription over to using a String media id
for identifying everything we should also use Strings in the browser
service to make it clear that it should re-use that field.
bug:17333205
Change-Id: I5fd5762bdad05068f5b1aa36074306b43432e686
Does all the updates in the bug except the loadIcon/loadBitmap
methods, which are removed per feedback from Sharkey.
bug:17205016
Change-Id: Ie84d4d25a59c6985ce16972c26c8d1e5c02ff5c9