Don't allow userID changes on upgrade

Changing userID's on upgrade lead to all sorts of bad behaviour, so,
don't allow it.

Bug: 28075981
Change-Id: I4861603f4607d7bd85fa24951a62a00dadd6eeec

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

@@ -13565,6 +13565,16 @@ public class PackageManagerService extends IPackageManager.Stub {
                 }
             }
 
+            // Check for shared user id changes
+            String invalidPackageName =
+                    getParentOrChildPackageChangedSharedUser(oldPackage, pkg);
+            if (invalidPackageName != null) {
+                res.setError(INSTALL_FAILED_SHARED_USER_INCOMPATIBLE,
+                        "Package " + invalidPackageName + " tried to change user "
+                                + oldPackage.mSharedUserId);
+                return;
+            }
+
             // In case of rollback, remember per-user/profile install state
             allUsers = sUserManager.getUserIds();
 
@@ -13839,15 +13849,6 @@ public class PackageManagerService extends IPackageManager.Stub {
             setInstallAndUpdateTime(newPackage, deletedPkgSetting.firstInstallTime,
                     System.currentTimeMillis());
 
-            // Check for shared user id changes
-            String invalidPackageName = getParentOrChildPackageChangedSharedUser(
-                    deletedPackage, newPackage);
-            if (invalidPackageName != null) {
-                res.setError(INSTALL_FAILED_SHARED_USER_INCOMPATIBLE,
-                        "Forbidding shared user change from " + deletedPkgSetting.sharedUser
-                                + " to " + invalidPackageName);
-            }
-
             // Update the package dynamic state if succeeded
             if (res.returnCode == PackageManager.INSTALL_SUCCEEDED) {
                 // Now that the install succeeded make sure we remove data