You can now clearly see when a tab is actually playing audio, although it’s unknown if this will work with plugins (the YouTube player being tested is the HTML5 trial that Google provides, not the Flash version most people use). The aesthetics may still change of course, given that this isn’t yet available in the Chrome Dev channel, and the functionality will likely continue to be expanded.
Beaufort notes Google says the purpose of this tweak is to exclude these tabs from those it discards when memory runs out. In other words, the company wants to better track of tabs that are “active” – just because the user hasn’t been clicking in a tab doesn’t mean he or she isn’t using it.
Source: The Next Web