Camera: Document 3.4 metadata selection logic.

 * structure asynchronously to the framework, using the processCaptureResult()

 * callback.

 *

 * Identical to @3.2::CaptureRequest, except that it contains @3.4::physCamSettings vector.

 *

 * Identical to @3.2::CaptureRequest, except that it contains

 * @3.4::physCamSettings vector.

 *

 * With 3.4 CaptureRequest, there can be multiple sources of metadata settings.

 * The @3.2::CaptureRequest v3_2 and each of the PhysicalCameraSetting in

 * physicalCameraSettings can contain settings, and each buffer may have

 * metadata settings from a different source.

 *

 * For both @3.2::CaptureRequest and PhysicalCameraSetting, the settings can be

 * passed from framework to HAL using either hwbinder or FMQ; both of the

 * structs have the fields fmqSettingsSize and settings to pass the metadata.

 * When metadata settings are passed using hwbinder, fmqSettingsSize == 0 and

 * settings field contains the metadata for the HAL to read. When metadata

 * settings comes from FMQ, fmqSettingsSize > 0 and HAL reads metadata from FMQ.

 * For the purposes of selecting which settings to use, it does not matter

 * whether it comes from hwbinder or FMQ. When the below specifications say that

 * v3_2 has settings or a PhysicalCameraSetting has settings, it could refer to

 * either hwbinder or FMQ, whichever is specified in the struct.

 *

 * Below is the logic that the HAL must follow for applying the metadata

 * settings when it receives a CaptureRequest request in

 * processCaptureRequest_3_4. Note that HAL must be capable of storing both the

 * request.v3_2 settings and the PhysicalCameraSetting settings for each

 * physical device.

 * - Case 1 - request.v3_2 has settings, request.physicalCameraSettings vector

 *   is empty:

 *   - Store the request.v3_2 settings, overwriting the previously stored

 *     request.v3_2 settings and clearing all previously stored physical device

 *     settings.

 *   - Apply the settings from the request.v3_2 to all buffers.

 * - Case 2 - request.v3_2 has settings, request.physicalCameraSettings vector

 *   is not empty:

 *   - Store the request.v3_2 settings, overwriting the previously stored

 *     request.v3_2 settings.

 *   - Each PhysicalCameraSetting in request.physicalCameraSettings must have

 *     settings; if not, return error.

 *   - For each PhysicalCameraSetting in request.physicalCameraSettings, store

 *     the settings, overwriting the previously stored settings for this

 *     physical camera; apply these settings to the buffers belonging to the

 *     stream for this device.

 *   - If there are any stored physical camera settings which do not correspond

 *     to one of the PhysicalCameraSetting in this request, clear them.

 *   - Apply the request.v3_2 settings to all buffers belonging to streams not

 *     covered by one of the PhysicalCameraSetting in this request.

 * - Case 3 - request.v3_2 does not have settings,

 *   request.physicalCameraSettings vector is empty:

 *   - Clear all previously stored physical device settings.

 *   - Apply the stored request.v3_2 settings to all buffers. If there is no

 *     stored request.v3_2 settings, return error.

 * - Case 4 - request.v3_2 does not have settings,

 *   request.physicalCameraSettings vector is not empty:

 *   - If request.physicalCameraSettings does not have the same set of physical

 *     cameras as the stored physical camera settings, return error.

 *   - Each PhysicalCameraSetting in request.physicalCameraSettings must not

 *     have settings; if any do have settings, return error.

 *   - For each PhysicalCameraSetting in request.physicalCameraSettings, apply

 *     the previously stored settings for this physical camera to the buffers

 *     belonging to the stream for this device.

 *   - Apply the stored request.v3_2 settings to all buffers belonging to

 *     streams not covered by one of the PhysicalCameraSetting in this request.

 *     If there is no stored request.v3_2 settings, return error.

 *

 * For the first request received by the HAL, only Case 1 and Case 2 are

 * allowed.

 */

struct CaptureRequest {

    /**

# ABI preserving changes to HALs during Android Q

f72d23278af99a2f6a9c1d40352b67dbf1f582282f799f88f7235dc7c13892b5 android.hardware.camera.device@3.2::ICameraDeviceSession

e96190f635b8458b92525bd6e040fec4ccbac22fdd4bc7274a9794ab976362f7 android.hardware.camera.device@3.4::types

f8a19622cb0cc890913b1ef3e32b675ffb26089a09e02fef4056ebad324d2b5d android.hardware.camera.device@3.4::types

da33234403ff5d60f3473711917b9948e6484a4260b5247acdafb111193a9de2 android.hardware.configstore@1.0::ISurfaceFlingerConfigs

21165b8e30c4b2d52980e4728f661420adc16e38bbe73476c06b2085be908f4c android.hardware.gnss@1.0::IGnssCallback

d702fb01dc2a0733aa820b7eb65435ee3334f75632ef880bafd2fb8803a20a58 android.hardware.gnss@1.0::IGnssMeasurementCallback