Refactor AttributeInfo into a proto

This is a no-op in functionality, but begins to pave the way for a proto output format for Stardoc.

RELNOTES: None.
PiperOrigin-RevId: 244020123
diff --git a/src/test/java/com/google/devtools/build/skydoc/BUILD b/src/test/java/com/google/devtools/build/skydoc/BUILD
index bcfc620..cff1161 100644
--- a/src/test/java/com/google/devtools/build/skydoc/BUILD
+++ b/src/test/java/com/google/devtools/build/skydoc/BUILD
@@ -28,6 +28,7 @@
         "//src/main/java/com/google/devtools/build/skydoc:skydoc_lib",
         "//src/main/java/com/google/devtools/build/skydoc/fakebuildapi",
         "//src/main/java/com/google/devtools/build/skydoc/rendering",
+        "//src/main/java/com/google/devtools/build/skydoc/rendering/proto:stardoc_output_java_proto",
         "//src/test/java/com/google/devtools/build/lib:testutil",
         "//src/test/java/com/google/devtools/build/lib/skylark:testutil",
         "//third_party:guava",