Google's next version of Android is revealed to have a "Dozing" feature which puts your phone sleep, effectively. What Google will do with Android M is to bring a Doze mode that sees when your phone has not been in use for an extended period of time. When you've accidentally left it on the counter over a long weekend away, for example. When your Android device senses this happening, it powers down all non-necessary functions. This could potentially extend battery life by 2x or more on your device.