Google's really into the idea of unifying all of its services into one overarching ecosystem. First it worked on making your Google+ profile the de facto standard for logging in to its various services, and now it's tackling its disparate interfaces and icon design.
Most of Google's web services and corresponding Android applications don't have matching iconography, but a new rumor suggests that the company is finally making it a priority to clean up this particular element of its business. According to Android Police, a few screenshot leaks and a webpage screenshot suggest that updated, unified icon designs are in the works, though there is no software-based evidence yet.
The screenshot shows new icons for all of Google's standard applications: Google Play Music, Books, Movies, and Games, in addition to Google+, Calendar, People, Chrome, YouTube, and more. Android Police's side-by-side icon comparison shows Google's web icons and its Android icons essentially meshing into one.
The rumor is by no means confirmed, but it makes sense: recent releases point toward an effort to make Google's apps and services carry a unified look and feel, and updated app icons would be no exception.