W3C’s HTML5 FAQ page might give some clues (see screenshot) about why Google buys Widevine, a DRM vendor that powers Netflix among others. What if Google adds DRM to HTML5 video?
Google did something similar when they bought On2 and open-sourced VP8 as part of WebM. This move pushed MPEGLA to make h.264 royalty-free for Web video. The iPad did the rest to accelerate adoption of HTML5/h.264 video in the web.
HTML5 video with DRM is what Youtube needs to convince content owners, movie studios in particular, that their content will be protected. Furthermore, HTML5 video with DRM, combined with cool HTML5 UIs, makes the Web Browser an ideal front-end for video on any screen. Where there is a browser, Google will make money with ads.
Adding open source DRM to HTML5 is consistent with Google’s web centric vision. Chrome OS is a perfect example of that vision, illustrated in this recent post on Google’s blog (with Eric Schmidt’s talk on the Chrome event this week).
I tend to think Google sees this acquisition more strategic than just adding DRM to GoogleTV.