Safe headset volume settings
Fixes for clang:
PackageInfo is a class, not a struct.
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
change default for unknown sources & verify apps

Change-Id: I04467c0c1ef3985b416f6e58013ddc3ce4137712