Understanding web pages better
I was under the assumption that Googlebot already used a headless Chrome to index websites for some time.Google used Chrome to generated page preview pictures (at index-time) to show the search terms (mouse over, but this feature is no more, as it seems). Some websites that shows you the user agent displayed the Chrome user-agent in the preview picture, back then (~2 years ago).it was called Instant Preview: http://googlesystem.blogspot.co.at/2010/11/google-instant-pr...details: https://sites.google.com/site/webmasterhelpforum/en/faq-inst...Google removed this useful feature in 04/2013 :(  As we’ve streamlined the results page, we’ve had to 
  remove certain features, such as Instant Previews.  

-- https://productforums.google.com/forum/#!topic/websearch/Aom...