Fixes for clang:
String16 is contained in the android namespace. Do not namespace prefix it
within the android namespace.
Explicitly specify which std classes are necessary to prevent ambiguous
type errors. (map, set)

Change-Id: I0d01477a976e770821ebae8847f8d11b132a15d6
Always call out to KeyguardHostView when something in our state changes.

KeyguardHostView already takes care to not add or remove the transport
control twice.
This should hopefully fix some conditions where the transport control
was still being shown although the media player already abandoned audio
focus.

Change-Id: Ib4577cdbfcea0a89efbbd0df70646afe8e677e0d