Add ActivityManager UidImportanceListener to libandroid

Add UidImportanceListener methods to libandroid for native apex use.

bug: 172942349
bug: 159172726
bug: 146507383

test: updated mediatranscoding's UidPolicy locally to use the new api,
and passed mediatranscodingservice unit tests.

Change-Id: I7ca76f057a83b5bcd634deb2408784d7b93e46fc
diff --git a/native/android/libandroid.map.txt b/native/android/libandroid.map.txt
index 3027eac..5b6039c 100644
--- a/native/android/libandroid.map.txt
+++ b/native/android/libandroid.map.txt
@@ -1,5 +1,9 @@
 LIBANDROID {
   global:
+    AActivityManager_addUidImportanceListener; # apex # introduced=31
+    AActivityManager_removeUidImportanceListener; # apex # introduced=31
+    AActivityManager_isUidActive; # apex # introduced=31
+    AActivityManager_getUidImportance; # apex # introduced=31
     AAssetDir_close;
     AAssetDir_getNextFileName;
     AAssetDir_rewind;