Add AlbumColumns.ARTIST_ID.

As pointed out by developers, we already have ARTIST, so we should
also have ARTIST_ID.

Bug: 130193406
Test: atest --test-mapping packages/providers/MediaProvider
Change-Id: I46b4de38a08a1ebb6951d8329070438d142888ad
diff --git a/api/current.txt b/api/current.txt
index 5997043..12362f0 100644
--- a/api/current.txt
+++ b/api/current.txt
@@ -38536,6 +38536,7 @@
     field public static final String ALBUM_ID = "album_id";
     field public static final String ALBUM_KEY = "album_key";
     field public static final String ARTIST = "artist";
+    field public static final String ARTIST_ID = "artist_id";
     field public static final String FIRST_YEAR = "minyear";
     field public static final String LAST_YEAR = "maxyear";
     field public static final String NUMBER_OF_SONGS = "numsongs";
diff --git a/core/java/android/provider/MediaStore.java b/core/java/android/provider/MediaStore.java
index bda6ed1..0b1647d 100644
--- a/core/java/android/provider/MediaStore.java
+++ b/core/java/android/provider/MediaStore.java
@@ -2676,7 +2676,13 @@
             public static final String ALBUM = "album";
 
             /**
-             * The artist whose songs appear on this album
+             * The ID of the artist whose songs appear on this album.
+             */
+            @Column(value = Cursor.FIELD_TYPE_INTEGER, readOnly = true)
+            public static final String ARTIST_ID = "artist_id";
+
+            /**
+             * The name of the artist whose songs appear on this album.
              */
             @Column(value = Cursor.FIELD_TYPE_STRING, readOnly = true)
             public static final String ARTIST = "artist";