Move api/*current.txt filegroups into api dir

The StubLibraries bp file is sufficiently humongous without them.

Bug: 169034951
Test: presubmit
Change-Id: I2809f94f950cdebb6c1fbf8de091e9d9443810d6
diff --git a/api/Android.bp b/api/Android.bp
index 54ff82c..54031da 100644
--- a/api/Android.bp
+++ b/api/Android.bp
@@ -1,7 +1,45 @@
+// Copyright (C) 2020 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package {
+    default_visibility: ["//visibility:private"],
+}
+
+// *-current.txt files for use by modules in other directories like cts
+filegroup {
+    name: "frameworks-base-api-current.txt",
+    srcs: ["current.txt"],
+    visibility: ["//visibility:public"],
+}
+
+filegroup {
+    name: "frameworks-base-api-system-current.txt",
+    srcs: ["system-current.txt"],
+    visibility: ["//visibility:public"],
+}
+
+filegroup {
+    name: "frameworks-base-api-system-removed.txt",
+    srcs: ["system-removed.txt"],
+    visibility: ["//visibility:public"],
+}
+
 genrule {
     name: "current-api-xml",
     tools: ["metalava"],
     srcs: ["current.txt"],
     out: ["current.api"],
     cmd: "$(location metalava) --no-banner -convert2xmlnostrip $(in) $(out)",
+    visibility: ["//visibility:public"],
 }