Merge "Update MediaDrm documentation for provideKeyResponse" into oc-dev am: ff8bf0cc

     * response is for an offline key request, a keySetId is returned that can be

     * used to later restore the keys to a new session with the method

     * {@link #restoreKeys}.

     * When the response is for a streaming or release request, null is returned.

     * When the response is for a streaming or release request, an empty byte array

     * is returned.

     *

     * @param scope may be a sessionId or keySetId depending on the type of the

     * response.  Scope should be set to the sessionId when the response is for either

     * streaming or offline key requests.  Scope should be set to the keySetId when

     * the response is for a release request.

     * @param response the byte array response from the server

     * @return If the response is for an offline request, the keySetId for the offline

     * keys will be returned. If the response is for a streaming or release request

     * an empty byte array will be returned.

     *

     * @throws NotProvisionedException if the response indicates that

     * reprovisioning is required