Add userId to key when type is USER

Before this cl, the app list couldn't distinguish different users
because all of them have the same key: USER.

This cl adds userId into key, to make sure the preference key
is unique.

Bug: 64605854
Test: RunSettingsRoboTests
Change-Id: Ia4de2ff85b214465a35f1983ca69a9280d053154

src/com/android/settings/fuelgauge/PowerUsageSummary.java

@@ -724,6 +724,8 @@ public class PowerUsageSummary extends PowerUsageBase implements
     String extractKeyFromSipper(BatterySipper sipper) {
         if (sipper.uidObj != null) {
             return extractKeyFromUid(sipper.getUid());
+        } else if (sipper.drainType == DrainType.USER) {
+            return sipper.drainType.toString() + sipper.userId;
         } else if (sipper.drainType != DrainType.APP) {
             return sipper.drainType.toString();
         } else if (sipper.getPackages() != null) {