Clarify rules about encryption of emulated storage.

     * fail (most commonly returning {@link #ENCRYPTION_STATUS_ACTIVE}).

     *

     * <p>This policy controls encryption of the secure (application data) storage area.  Data

     * written to other areas (e.g. the directory returned by

     * {@link android.os.Environment#getExternalStorageDirectory()} may or may not be encrypted.

     * written to other storage areas may or may not be encrypted, and this policy does not require

     * or control the encryption of any other storage areas.

     * There is one exception:  If {@link android.os.Environment#isExternalStorageEmulated()} is

     * {@code true}, then the directory returned by

     * {@link android.os.Environment#getExternalStorageDirectory()} must be written to disk

     * within the encrypted storage area.

     *

     * <p>Important Note:  On some devices, it is possible to encrypt storage without requiring

     * the user to create a device PIN or Password.  In this case, the storage is encrypted, but

    /**

     * Returns whether the device has an external storage device which is

     * emulated. If true, the device does not have real external storage

     * and certain system services such as the package manager use this

     * emulated. If true, the device does not have real external storage, and the directory

     * returned by {@link #getExternalStorageDirectory()} will be allocated using a portion of

     * the internal storage system.

     *

     * <p>Certain system services, such as the package manager, use this

     * to determine where to install an application.

     *

     * <p>Emulated external storage may also be encrypted - see

     * {@link android.app.admin.DevicePolicyManager#setStorageEncryption(

     * android.content.ComponentName, boolean)} for additional details.

     */

    public static boolean isExternalStorageEmulated() {

        if (mIsExternalStorageEmulated == null) {