This is Matthias Duarte at work. A "bar" has been present in webOS since the beginning. In 1.x and 2.x, you could press the app name or swipe down from the top of the screen to view the app's menu or other options like Cut n Paste, logging in or out, etc. In 3.x, the top bar was expanded to include notifications and dashboards, greatly improving multitasking. In all three versions, the top bar also had quick access to system settings (again with a tap or a swipe down) such as WiFi, Bluetooth, VPN, or airplane mode.

Such a shame that Palm/HP let Duarte go. He's really bringing the best of webOS to Android. The classic webOS experience (which was a little muddled up with the Touchpad) only had buttons for power and volume. Everything else was done tapping or swiping on the screen or gesture area. Now, Duarte is doing away with hardware buttons on Android and who knows, maybe a gesture area is next.