Package manager changes to store and update user information.

Some API stubs for managing users and storing their details.
List of users is stored in an xml file.
Each user's properties are stored in a separate xml file.

Some unit tests for modifying the XML files.

Change-Id: If2ce2420723111bd426f6762def3c2afc19a0ae5
diff --git a/core/java/android/app/IActivityManager.java b/core/java/android/app/IActivityManager.java
index 61e6fc8..f07d9c6 100644
--- a/core/java/android/app/IActivityManager.java
+++ b/core/java/android/app/IActivityManager.java
@@ -342,6 +342,9 @@
     public int startActivitiesInPackage(int uid,
             Intent[] intents, String[] resolvedTypes, IBinder resultTo) throws RemoteException;
 
+    // Multi-user APIs
+    public boolean switchUser(int userid) throws RemoteException;
+
     /*
      * Private non-Binder interfaces
      */
@@ -557,4 +560,5 @@
     int START_ACTIVITIES_TRANSACTION = IBinder.FIRST_CALL_TRANSACTION+120;
     int START_ACTIVITIES_IN_PACKAGE_TRANSACTION = IBinder.FIRST_CALL_TRANSACTION+121;
     int ACTIVITY_SLEPT_TRANSACTION = IBinder.FIRST_CALL_TRANSACTION+122;
+    int SWITCH_USER_TRANSACTION = IBinder.FIRST_CALL_TRANSACTION+123;
 }