Allow privileged callers to schedule a backup pass for any app.

        Log.d(TAG, "dataChanged packageName=" + packageName);

        HashSet<ApplicationInfo> targets = mBackupParticipants.get(Binder.getCallingUid());

        // If the caller does not hold the BACKUP permission, it can only request a

        // backup of its own data.

        HashSet<ApplicationInfo> targets;

        if ((mContext.checkPermission("android.permission.BACKUP", Binder.getCallingPid(),

                Binder.getCallingUid())) == PackageManager.PERMISSION_DENIED) {

            targets = mBackupParticipants.get(Binder.getCallingUid());

        } else {

            // a caller with full permission can ask to back up any participating app

            // !!! TODO: allow backup of ANY app?

            if (DEBUG) Log.v(TAG, "Privileged caller, allowing backup of other apps");

            targets = new HashSet<ApplicationInfo>();

            int N = mBackupParticipants.size();

            for (int i = 0; i < N; i++) {

                HashSet<ApplicationInfo> s = mBackupParticipants.valueAt(i);

                if (s != null) {

                    targets.addAll(s);

                }

            }

        }

        if (targets != null) {

            synchronized (mQueueLock) {

                // Note that this client has made data changes that need to be backed up