As you might know, Chrome for Android allows you to save websites on your home screen for easy access. The first Android O Developer Preview added support for a new 'Adaptive icons' feature, and Chrome now appears to be taking advantage of it for home screen shortcuts.
Adding a site to the home screen on Android 7.1.2.
On Android 7.1 and below, icons on the home screen just use whatever icon the website provided, without any kind of layer or mask applied. With Android O, the icons appear to match whatever your phone's icon mask is. On the Pixel, the default icon mask is a circle.
Adding a site to the home screen on Android O.
The new mask works well for websites with a transparent icon (like this site), but for others that implement their own backgrounds, the result might not look pretty. In addition, Chrome shortcuts now have a Chrome icon in the bottom-right corner (except for Progressive Web Apps).
I definitely like this change, but let us know in the comments below what you think.