libbinder: add libactivitymanager_aidl

Start splitting out activity manager. This adds an empty library so it
can be added in internal branches where the dependency is needed.

Bug: 183654927
Test: N/A
Change-Id: I1f2334de38b196c28d74f324dde72d55b9648f90
diff --git a/libs/binder/Android.bp b/libs/binder/Android.bp
index 2715d6a..05c32b3 100644
--- a/libs/binder/Android.bp
+++ b/libs/binder/Android.bp
@@ -296,3 +296,14 @@
         "liblog",
     ],
 }
+
+// TODO(b/183654927): initially empty lib to work around some merge conflicts
+cc_library {
+    name: "libactivitymanager_aidl",
+    srcs: [],
+    shared_libs: [
+        "libbinder",
+        "libutils",
+        "liblog",
+    ],
+}