Added keep-uninstalled-packages DO policy

This policy allows DO to specify a list of apps to cache even without being
installed on any user.

Bug: 23938464
Change-Id: I2eeab7f148409739fc23a5c44e955ad12b63fd04
diff --git a/core/java/android/content/pm/PackageManagerInternal.java b/core/java/android/content/pm/PackageManagerInternal.java
index bf70d6c..905ac5e 100644
--- a/core/java/android/content/pm/PackageManagerInternal.java
+++ b/core/java/android/content/pm/PackageManagerInternal.java
@@ -16,7 +16,7 @@
 
 package android.content.pm;
 
-import android.annotation.NonNull;
+import java.util.List;
 
 /**
  * Package manager local system service interface.
@@ -115,4 +115,11 @@
      */
     public abstract void grantDefaultPermissionsToDefaultSimCallManager(String packageName,
             int userId);
+
+    /**
+     * Sets a list of apps to keep in PM's internal data structures and as APKs even if no user has
+     * currently installed it. The apps are not preloaded.
+     * @param packageList List of package names to keep cached.
+     */
+    public abstract void setKeepUninstalledPackages(List<String> packageList);
 }