Floating Apps (multitasking) is described as 'Floating Apps on android system, also has own youtube, flash and extras'. There are three alternatives to Floating Apps (multitasking) for Mac, Windows, Chrome OS, Google Chrome and Linux. The best alternative is Fluid Browser. It's not free, so if you're looking for a free alternative, you could try Floating for YouTube™ Extension.
Fluid is a floating browser built to view your favorite media like Netflix, Youtube and Hulu right alongside your work. Fluid works just like any other browser, however, once active Fluid only shows your media or web content hiding away all other features of thebrowser.