AI 143800: am: CL 143748 Fix issue #1743326 (More battery stats)

Adds stats for:
  - Number of raw user events that have happened in the system.
  - Number of times user activity has been reported, dividied by UID and type of activity.
  - Duration of screen brightness levels in 4 buckets.
  - Per-UID tracking of who has turned on Wifi and how long we can attribute it being on because of them.
  Original author: hackbod
  Merged from: //branches/cupcake/...

Automated import of CL 143800

services/java/com/android/server/WindowManagerService.java

@@ -5085,6 +5085,11 @@ public class WindowManagerService extends IWindowManager.Stub implements Watchdo
                         } else {
                             eventType = LocalPowerManager.OTHER_EVENT;
                         }
+                        try {
+                            mBatteryStats.noteInputEvent();
+                        } catch (RemoteException e) {
+                            // Ignore
+                        }
                         mPowerManager.userActivity(curTime, false, eventType);
                         switch (ev.classType) {
                             case RawInputEvent.CLASS_KEYBOARD: