Russia is developing weaponized ground drones, including some big amphibious models like the one you can see here. Add the thousands of combat air drones from many nations already flying through the world and it's not crazy to think in a full robotic war happening before 2020 somewhere in the world.
Some of these ground drones are larger than the models recently demonstrated by the Pentagon. Not that larger means better, but just imagine this beast in 1944, during the invasion of Normandy.
The small one is similar to the weaponized iRobots, but with a space rover-like power train.