Surprised? I was too, when I came across this long article explaining such a possibility. “What if Chrome was in fact a repackaging of their search crawler; affectionately known as GoogleBot, for the consumer environment?” author asks.
For that, the bot needs to act similar to a browser. Google had to build a faster and better browser for their core business, to index the web and Chrome was a expected/unexpected by product of this.
The article here has a detailed and more technical explanation of this. Take a look and let me know what you think!