Third-party search engine logo support is hitting Android for users when they enable any other search engine other than Google as their default selection. Discovered in the Chromium bug tracker, details show the Yandex logo on the new tab page in Chrome when Yandex is configured as the default search engine, though it seems the logo support would be there for other options too, such as Bing.
Prior to these changes that Google has now started to implement, users would see a blank new tab page, save for their recently viewed pages, if they had a different search engine set to default that wasn't Google, but it appears Yandex filed a request earlier this year on the Chromium bug tracker to allow third-party logos so that users would see the logo of whatever search engine they chose to have as default, and it looks like Google is finally preparing to make these changes user-facing and visible.
This is a change that Google hasn't yet rolled out to users in the stable, beta, dev, or canary channels, but it is suggested that once Google launches Chrome 61 for Android that third-party logo support for the new tab page will be included. While many users likely keep Google as the default search engine option, there's no doubt that there are probably some users who would rather see the correct logo if they don't keep Google for this purpose. This might seem like a minor thing from the user side, but for Yandex it's a potentially huge adjustment that works in its favor, especially considering the recent change in Russia that asks users after the initial Chrome installation to pick a search engine prior to setting up the rest of the browser. Should users end up picking Yandex as the default within the region, opening up new tabs will soon show the correct logo, which if nothing else at least puts more awareness out there for Yandex in the way that having Google's logo on the new tab page does so for Google. If you use a search engine other than Google, keep an eye out for new tabs to show the correct icon soon.