Google Inc has agreed to refund at least $19 million to settle charges that it unfairly billed parents for purchases that their children made while playing video games like Ice Age Village and Air Penguins on mobile devices. Federal Trade Commission said on Thursday that the Internet giant had also agreed to modify its billing practices to ensure that parents know, and agree to, purchases that their children make. The FTC settled a similar case with Apple Inc in January. Apple agreed to refund to customers at least $32.5 million in unauthorized charges made by children and to change its billing practices to require consent from parents for in-app spending.