libmedia: read from parcel only when there's a data available.

template <typename T>

static void readFromParcel(const Parcel &data, Vector<T> *items) {

    size_t size = (size_t)data.readUint32();

    for (size_t i = 0; i < size; i++) {

    for (size_t i = 0; i < size && data.dataAvail() > 0; i++) {

        T item;

        item.readFromParcel(data);

        items->add(item);