Emit event log message when switching users.

Change-Id: I8e521e177b0e17e2ab9e033e0ff8bc421cd5f784
diff --git a/services/java/com/android/server/am/ActivityManagerService.java b/services/java/com/android/server/am/ActivityManagerService.java
index d2cd646..db64a9a 100644
--- a/services/java/com/android/server/am/ActivityManagerService.java
+++ b/services/java/com/android/server/am/ActivityManagerService.java
@@ -14229,6 +14229,7 @@
                     startHomeActivityLocked(userId);
                 }
 
+                EventLogTags.writeAmSwitchUser(userId);
                 getUserManagerLocked().userForeground(userId);
                 sendUserSwitchBroadcastsLocked(oldUserId, userId);
                 if (needStart) {