Camera: clarify external camera device ID requirements

 * where

 *   - <major>/<minor> is the provider HAL HIDL version,

 *   - <type> is the type of devices this provider knows about, such as

 *     "internal", "legacy", "usb", or "remote"

 *     "internal", "legacy", "external", or "remote"

 *   - <instance> is a non-negative integer starting from 0 to disambiguate

 *     between multiple HALs of the same type.

 *

 * The "legacy" type is only used for passthrough legacy HAL mode, and must

 * not be used by a standalone binderized HAL.

 *

 * The device instance names enumerated by the provider must be of the form

 * The device instance names enumerated by the provider in getCameraIdList() or

 * ICameraProviderCallback::cameraDeviceStatusChange() must be of the form

 * "device@<major>.<minor>/<type>/<id>" where

 * <major>/<minor> is the HIDL version of the interface. <id> is either a small

 * incrementing integer for "internal" device types, with 0 being the main

 * back-facing camera and 1 being the main front-facing camera, if they exist.

 * Or, for external devices such as type "usb", a unique serial number that can

 * be used to identify the device reliably when it is disconnected and

 * reconnected. Multiple providers may not enumerate the same device ID.

 * Or, for external devices, a unique serial number (if possible) that can be

 * used to identify the device reliably when it is disconnected and reconnected.

 *

 * Multiple providers must not enumerate the same device ID.

 */

interface ICameraProvider {

    getVendorTags() generates (Status status, vec<VendorTagSection> sections);

    /**

     * getCameraDeviceList:

     * getCameraIdList:

     *

     * Returns the list of internal camera device interfaces known to this

     * camera provider. These devices can then be accessed via the hardware

# ABI preserving changes to HALs during Android P

cf72ff5a52bfa4d08e9e1000cf3ab5952a2d280c7f13cdad5ab7905c08050766 android.hardware.camera.metadata@3.2::types

7b4723305354193b889a24153e1292fec62d5a5127bdfba08a5a27440f092de9 android.hardware.camera.provider@2.4::ICameraProvider

6fa9804a17a8bb7923a56bd10493a5483c20007e4c9026fd04287bee7c945a8c android.hardware.gnss@1.0::IGnssCallback

fb92e2b40f8e9d494e8fd3b4ac18499a3216342e7cff160714c3bbf3660b6e79 android.hardware.gnss@1.0::IGnssConfiguration

251594ea9b27447bfa005ebd806e58fb0ae4aad84a69938129c9800ec0c64eda android.hardware.gnss@1.0::IGnssMeasurementCallback