Google won’t allow DRM in an open-source project. Samuel Maddock is building a browser called Metastream, an “Electron-based (Chromium derived), MIT-licensed browser hosted on GitHub. Its main feature is the ability to playback videos on the web, synchronized with other peers. Each client runs its own instance of the Metastream browser and transmits playback information to keep them in sync—no audio or video content is sent.” He sent a request to Google for a license to implement Widevine in his browser, and received this reply, “I’m sorry but we’re not supporting an open source solution like this”, four months later.
See also “After years of insisting that DRM in HTML wouldn’t block open source implementations, Google says it won’t support open source implementations” by Cory Doctorow for more on the story.