Add bound checks to utf16_to_utf8

Bug: 29250543
Change-Id: I518e7b2fe10aaa3f1c1987586a09b1110aff7e1a
(cherry picked from commit 7e93b2ddcb49b5365fbe1dab134ffb38e6f1c719)

status_t Parcel::readByteVector(std::vector<uint8_t>* val) const {
 return readByteVectorInternal(this, val);
}

status_t Parcel::readByteVector(std::vector<uint8_t>* val) const {
 return readByteVectorInternal(this, val);
}
