Google has the most popular web browser in the world, in Chrome. And it's available on just about every platform, even iOS and Android. Google is always tinkering with things. Whether it be the features of the browser, incorporating Google Now, or changing up the UI. There are always changes being made to Chrome. That's what we have the beta and developer channels of Chrome for. To allow Google to test out new features and get them bug free, as well them being good enough for the stable version, before putting them in the stable version of Chrome.
Back in August, Google began rolling out updates to the developer and beta which changed up the new tab page. Ordinarily there we would see 6 thumbnails of the sites that you visit most often. Google had swapped those out for 8 icons of your most visited sites. And it would pull in the favicon for the site, or just show the first letter of the site's name. Allowing you to see even more websites in the new tab page, without it being too cluttered. It also has the Google Search bar in the center, so you can quickly do a search if you so wish.
Now it appears that Google is rolling out this update to the stable channel of Chrome on Android. However, it appears that not everyone has the update. So this could either be a staged rollout or a simple server flip for the new tab page. If you'd like to get the new setup for the new tab page, you can do so in the chrome://flags page actually. Find the "Enable large icons on the New Tab page". Now this should be set to default, if it isn't, just set it to default and you should see the update. It's more than likely that this is indeed a server-side update for Google Chrome. Seeing as we haven't seen a new update for the app recently. So for those of you using Chrome as your default web browser, you should begin seeing an updated new tab page in the very near future (read: next few days).