DRTVWR-489-emoji: declaring this variable as a U16 leads to a warning (and...

DRTVWR-489-emoji: declaring this variable as a U16 leads to a warning (and therefore an error) but only on 32bit Windows builds - 64bit is fine.  I don't know why that's the case (should be both surely) but in any case, I think the variable should be declared as a size_t