Google is in the process of developing a new feature that lets users mute the audio notifications in Chrome’s browser tabs. This new feature is available to Chromium users and could eventually come to Chrome’s Canary platform, which means that a stable release probably won’t be happening anytime soon.
Here’s an overview of the feature from Google’s release log:
This change consolidates all of the existing media indicator UI into a new MediaIndicatorButton class. When the indicator is transitioned to the audio playing or muting state, the button functionality activates; and, when clicked, will toggle tab-wide audio muting. Otherwise, the view only serves to paint the indicator icon with all mouse/gesture events handled by Tab (its parent View).
Google started working on this option after receiving feedback from Chrome users saying they expected it to be available as a stock feature.
(via Peter Kasting+)