Enabled annotations for Metalava based api-stubs.

Test: m -j metalava-api-stubs-docs
Bug: b/78245848
Change-Id: I4ba661900a52f246fc0191c31aabfc96b89fa2db
diff --git a/Android.bp b/Android.bp
index cb32b36..773c9b7 100644
--- a/Android.bp
+++ b/Android.bp
@@ -1116,6 +1116,9 @@
     local_sourcepaths: frameworks_base_subdirs,
     installable: false,
     metalava_enabled: true,
+    metalava_annotations_enabled: true,
+    metalava_previous_api: ":public-api-for-metalava-annotations",
+    metalava_merge_annotations_dir: "tools/metalava/manual",
 }
 
 droiddoc {