Audio V4: Add its own function to open the primary device

import android.hardware.audio.common@4.0;

import IDevice;

import IPrimaryDevice;

/** This factory allows a HAL implementation to be split in multiple independent

 *  devices (called module in the pre-treble API).

 *  Each device name is arbitrary, provided by the vendor's audio_policy_configuration.xml

 *  and only used to identify a device in this factory.

 *  The framework must not interpret the name, treating it as a vendor opaque data

 *  with the following exceptions:

 *  - the "primary" device must always be present and is the device used by the telephony framework.

 *  with the following exception:

 *  - the "r_submix" device that must be present to support policyMixes (Eg: Android projected).

 *    Note that this Device is included by default in a build derived from AOSP.

 *

     * @return result the interface for the created device.

     */

    openDevice(string device) generates (Result retval, IDevice result);

    /**

     * Opens the Primary audio device that must be present.

     * This function is not optional and must return successfully the primary device.

     *

     * This device must have the name "primary".

     *

     * The telephony stack uses this device to control the audio during a voice call.

     *

     * @return retval operation completion status. Must be SUCCESS.

     *         For debuging, return INVALID_ARGUMENTS if there is no corresponding

     *         hardware module found, NOT_INITIALIZED if an error occurred

     *         while opening the hardware module.

     * @return result the interface for the created device.

     */

    openPrimaryDevice() generates (Result retval, IPrimaryDevice result);

};