Merge changes I72996d88,I2be08aa1 into udc-dev

* changes:
  Referring to manifest attribute for updateowner
  Turn on update owner enforcement by default

core/java/android/content/pm/PackageInstaller.java

@@ -2991,6 +2991,10 @@ public class PackageInstaller {
          * The update ownership enforcement can only be enabled on initial installation. Set
          * this to {@code true} on package update is a no-op.
          *
+         * Apps may opt themselves out of update ownership by setting the
+         * <a href="https://developer.android.com/guide/topics/manifest/manifest-element.html#allowupdateownership">android:alllowUpdateOwnership</a>
+         * attribute in their manifest to <code>false</code>.
+         *
          * Note: To enable the update ownership enforcement, the installer must have the
          * {@link android.Manifest.permission#ENFORCE_UPDATE_OWNERSHIP ENFORCE_UPDATE_OWNERSHIP}
          * permission.

services/core/java/com/android/server/pm/PackageManagerService.java

@@ -7273,7 +7273,7 @@ public class PackageManagerService implements PackageSender, TestUtilityService
         final long token = Binder.clearCallingIdentity();
         try {
             return DeviceConfig.getBoolean(NAMESPACE_PACKAGE_MANAGER_SERVICE,
-                    PROPERTY_IS_UPDATE_OWNERSHIP_ENFORCEMENT_AVAILABLE, false /* defaultValue */);
+                    PROPERTY_IS_UPDATE_OWNERSHIP_ENFORCEMENT_AVAILABLE, true /* defaultValue */);
         } finally {
             Binder.restoreCallingIdentity(token);
         }