Add support for power keys, improve behavior of virtual keys.

The platform now knows how to deal with a platform key, which at this
point is "just like end call, but don't end a call."

Also improve the handling of virtual keys, to allow for canceling when
sliding off into the display and providing haptic feedback.

Finally fixes a bug where the raw x and y in motion event were not
always set which caused the status bar to not work.

services/java/com/android/server/InputDevice.java

@@ -213,7 +213,7 @@ public class InputDevice {
             
             // We only consider the first pointer when computing the edge
             // flags, since they are global to the event.
-            if (action != MotionEvent.ACTION_DOWN) {
+            if (action == MotionEvent.ACTION_DOWN) {
                 if (scaled[MotionEvent.SAMPLE_X] <= 0) {
                     edgeFlags |= MotionEvent.EDGE_LEFT;
                 } else if (scaled[MotionEvent.SAMPLE_X] >= dispW) {