Make AudioManager.FLAG_FROM_KEY @SystemApi for Module

Bug: 160682430
Test: m update-api
Change-Id: Ibce0ee78713cef698a188d2218189dbf871b9472
diff --git a/non-updatable-api/module-lib-current.txt b/non-updatable-api/module-lib-current.txt
index 45ff6d3..3c0b955 100644
--- a/non-updatable-api/module-lib-current.txt
+++ b/non-updatable-api/module-lib-current.txt
@@ -31,6 +31,14 @@
 
 }
 
+package android.media {
+
+  public class AudioManager {
+    field public static final int FLAG_FROM_KEY = 4096; // 0x1000
+  }
+
+}
+
 package android.os {
 
   public class Binder implements android.os.IBinder {