Tweaks to fingerprint AIDL

1) Explicit numbering for Error enum, which contains intentionally
   skipped entries for backwards compatibility
2) Documentation for vendorCode. The vendorCodes must have a well
   defined behavior with the array API for things like GSI to work,
   e.g. generic system image with non-generic HAL implementation -
   with this explicit requirement, both components, as long as the
   contract is followed, would allow proper string feedback to be
   loaded/shown.

Bug: 168843220
Test: Builds
Change-Id: Ie78e42b926351a03162a4a6e40f3325641c34609
diff --git a/biometrics/fingerprint/aidl/android/hardware/biometrics/fingerprint/Error.aidl b/biometrics/fingerprint/aidl/android/hardware/biometrics/fingerprint/Error.aidl
index 014a4c0..4fe7f5f 100644
--- a/biometrics/fingerprint/aidl/android/hardware/biometrics/fingerprint/Error.aidl
+++ b/biometrics/fingerprint/aidl/android/hardware/biometrics/fingerprint/Error.aidl
@@ -34,28 +34,28 @@
      * The implementation is unable to process the request. For example, invalid arguments were
      * supplied.
      */
-    UNABLE_TO_PROCESS,
+    UNABLE_TO_PROCESS = 2,
 
     /**
      * The current operation took too long to complete.
      */
-    TIMEOUT,
+    TIMEOUT = 3,
 
     /**
      * No space available to store additional enrollments.
      */
-    NO_SPACE,
+    NO_SPACE = 4,
 
     /**
      * The operation was canceled. See common::ICancellationSignal.
      */
-    CANCELED,
+    CANCELED = 5,
 
     /**
      * The implementation was unable to remove an enrollment.
      * See ISession#removeEnrollments.
      */
-    UNABLE_TO_REMOVE,
+    UNABLE_TO_REMOVE = 6,
 
     /**
      * Reserved to maintain backwards compatibility. See ISessionCallback#onLockoutTimed instead.
diff --git a/biometrics/fingerprint/aidl/android/hardware/biometrics/fingerprint/ISessionCallback.aidl b/biometrics/fingerprint/aidl/android/hardware/biometrics/fingerprint/ISessionCallback.aidl
index 33a93e5..74792d8 100644
--- a/biometrics/fingerprint/aidl/android/hardware/biometrics/fingerprint/ISessionCallback.aidl
+++ b/biometrics/fingerprint/aidl/android/hardware/biometrics/fingerprint/ISessionCallback.aidl
@@ -38,7 +38,10 @@
      * operation.
      *
      * @param info See the AcquiredInfo enum.
-     * @param vendorCode Only valid if info == AcquiredInfo::VENDOR.
+     * @param vendorCode Only valid if info == AcquiredInfo::VENDOR. The vendorCode must be used to
+     *                   index into the configuration
+     *                   com.android.internal.R.array.fingerprint_acquired_vendor that's installed
+     *                   on the vendor partition.
      */
     void onAcquired(in AcquiredInfo info, in int vendorCode);
 
@@ -58,7 +61,10 @@
      * an Error::CANCELED message.
      *
      * @param error See the Error enum.
-     * @param vendorCode Only valid if error == Error::VENDOR.
+     * @param vendorCode Only valid if error == Error::VENDOR. The vendorCode must be used to index
+     *                   into the configuration
+     *                   com.android.internal.R.fingerprint_error_vendor that's installed on the
+     *                   vendor partition.
      */
     void onError(in Error error, in int vendorCode);