Merge "Docs: fixed example in SharedPreferencesBackupHelper"

 *     // identify the SharedPreferenceBackupHelper's data.

 *     static final String MY_PREFS_BACKUP_KEY = "myprefs";

 *

 *     // Simply allocate a helper and install it

 *     void onCreate() {

 *     // Allocate a helper and install it.

 *     public void onCreate() {

 *         SharedPreferencesBackupHelper helper =

 *                 new SharedPreferencesBackupHelper(this, PREFS_DISPLAY, PREFS_SCORES);

 *         addHelper(MY_PREFS_BACKUP_KEY, helper);