Add filegroup for UnsupportedAppUsage and its deps

This is in preparation for replacing all instances of
android.annotation.UnsupportedAppUsage with
dalvik.annotation.compat.UnsupportedAppUsage.

Test: m
Change-Id: Iea5977de3cc213d0a0359055297d2c01d00ad5de
diff --git a/JavaLibrary.bp b/JavaLibrary.bp
index 2066c42..53d0a10 100644
--- a/JavaLibrary.bp
+++ b/JavaLibrary.bp
@@ -702,3 +702,14 @@
     name: "timezone-host",
     srcs: [":timezone_host_files"],
 }
+
+// The source files that contain the UnsupportedAppUsage annotation and its dependencies.
+filegroup {
+    name: "unsupportedappusage_annotation_files",
+    srcs: [
+        "dalvik/src/main/java/dalvik/annotation/compat/UnsupportedAppUsage.java",
+        "dalvik/src/main/java/dalvik/system/VersionCodes.java",
+        "luni/src/main/java/libcore/api/CorePlatformApi.java",
+        "luni/src/main/java/libcore/api/IntraCoreApi.java",
+    ],
+}
\ No newline at end of file