Resource memory optimization.

Don't ever need the cached UTF-16 string conversions on the
device.  Don't need to create those strings, and don't need
to create the lookup array for them at all.  This requires
fixing all of the remaining places in the platform where we
interacted with the resources with the blind assumption that
the strings are UTF-16.

Change-Id: Ia0e5a150499837471e494e85b23b05fa06e0cf1d