A small hint in an Android source code commit revealed that Google may be working on a multi-windows feature for a future version of Android. The developer's statement doesn't say too much about it other than mention the word "multiwindows," but this just adds to another hint back from October last year that also pointed to multi-windows coming to stock Android.
Samsung has experimented with multi-windows on its tablets before, going from two to even four different apps running at the same time. The idea of showing multiple apps on a larger tablet screen would have made Android tablets more useful and more productive in the early stage of their life. It would have also solved the tablet app problem by using phone apps that would fit better on a smaller part of a large screen rather than being expanded to fit a 10" screen.
Samsung's multi-windows feature had two critical flaws, though. One was performance. Tablets seemed to slow down significantly when using multiple apps at the same time. However, it was never clear whether this was because of poor coding from Samsung, Android not being performance-optimized enough at the time, the processors not being fast enough to handle multi-windows, or a combination of all of these issues.
The second flaw with Samsung's multi-windows system was that it only worked with Samsung's apps, or apps that used Samsung's own SDK, in order to utilize the custom multi-windows APIs.
Google could be implementing this feature natively into Android at a time when Android has largely solved its performance issue thanks to the new runtime's Ahead-Of-Time compilation and other improvements over the years. Processors that are going into tablets are much faster as well, which should also help to run multiple apps at the same time.
Competitors such as Microsoft, Canonical, and likely Apple soon, too (with its rumored "iPad Pro" device), have used or will use multi-windows in their mobile operating systems as they become more mature and can work with more powerful hardware.
The question is how far Google is going to take this feature, and whether the company will make it so powerful that it could lead to Android becoming much more appealing as a PC operating system. Tablet sales have been stagnating or dropping lately, so perhaps Google will need to consider going into PCs with Android, as a more "advanced" operating system than Chrome OS.
Google announced last year that Chrome OS will support Android apps, but it doesn't look like all Android apps can work by default, once Google modifies some code inside Chrome OS. Instead, so far we've only seen a handful of Android apps that have been pre-approved by Google for Chrome OS. If Google can't make all Android apps work inside Chrome OS, then perhaps Android could be more suited for the PC and as a competitor to Windows and Mac OS X, for those users who want to use an operating system that doesn't limit them to the Web.
Google will likely announce a new major version of Android at the next Google I/O event, along with the multi-windows feature.