http://www.pcmag.com/article2/0,2817,2500377,00.asp
"The reason for this is to protect our users. We've heard too frequently that many users are unaware of the extensions they have installed, whether this is due to sideloading, installation by phishing, or simply the user forgetting how many and which are installed. Unfortunately, extensions consume computing resources, and may have significant security, privacy, and performance impacts. Because of this, we've decided we need to increase user visibility."