More than two years ago, a pair of Google researchers started pushing the company to release a chatbot built on technology more powerful than anything else available at the time. The conversational computer program they had developed could confidently debate philosophy and banter about its favorite TV shows, while improvising puns about cows and horses. The researchers, Daniel De Freitas and Noam Shazeer, told colleagues that chatbots like theirs, supercharged by recent advances in artificial intelligence, would revolutionize the way people searched the internet and interacted with computers, according to people who heard the remarks.