Remove code related to db Upgrade callback.

MultiPart: 4/5
Change-Id: Iba2b0c1c30aef49d0c183eb42702f2ce4300811f
diff --git a/v23/syncbase/nosql/upgrader.go b/v23/syncbase/nosql/upgrader.go
deleted file mode 100644
index d530038..0000000
--- a/v23/syncbase/nosql/upgrader.go
+++ /dev/null
@@ -1,55 +0,0 @@
-// Copyright 2015 The Vanadium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// +build java android
-
-package nosql
-
-import (
-	"fmt"
-	"runtime"
-
-	"v.io/v23/syncbase/nosql"
-
-	jutil "v.io/x/jni/util"
-)
-
-// GoUpgrader converts a provided Java SchemaUpgrader into a Go SchemaUpgrader.
-func GoUpgrader(env jutil.Env, jUpgrader jutil.Object) nosql.SchemaUpgrader {
-	if jUpgrader.IsNull() {
-		return nil
-	}
-	// Reference Java upgrader; it will be de-referenced when the Go upgrader
-	// created below is garbage-collected (through the finalizer callback we
-	// setup just below).
-	jUpgrader = jutil.NewGlobalRef(env, jUpgrader)
-	upgrader := &jniUpgrader{
-		jUpgrader: jUpgrader,
-	}
-	runtime.SetFinalizer(upgrader, func(u *jniUpgrader) {
-		env, freeFunc := jutil.GetEnv()
-		defer freeFunc()
-		jutil.DeleteGlobalRef(env, u.jUpgrader)
-	})
-	return upgrader
-}
-
-type jniUpgrader struct {
-	jUpgrader jutil.Object
-}
-
-func (u *jniUpgrader) Run(db nosql.Database, oldVersion, newVersion int32) error {
-	env, freeFunc := jutil.GetEnv()
-	defer freeFunc()
-	jdb, ok := db.(*jniDatabase)
-	if !ok {
-		return fmt.Errorf("Unknown database type: %T", db)
-	}
-	jDatabase, err := javaDatabase(env, jdb)
-	if err != nil {
-		return err
-	}
-	databaseSign := jutil.ClassSign("io.v.v23.syncbase.nosql.Database")
-	return jutil.CallVoidMethod(env, u.jUpgrader, "run", []jutil.Sign{databaseSign, jutil.IntSign, jutil.IntSign}, jDatabase, oldVersion, newVersion)
-}
diff --git a/v23/syncbase/nosql/util.go b/v23/syncbase/nosql/util.go
index 015e760..703c73c 100644
--- a/v23/syncbase/nosql/util.go
+++ b/v23/syncbase/nosql/util.go
@@ -70,12 +70,6 @@
 	if err := jutil.GoVomCopy(env, jMetadata, jSchemaMetadataClass, &metadata); err != nil {
 		return nil, err
 	}
-	upgraderSign := jutil.ClassSign("io.v.v23.syncbase.nosql.SchemaUpgrader")
-	jUpgrader, err := jutil.CallObjectMethod(env, jSchema, "getUpgrader", nil, upgraderSign)
-	if err != nil {
-		return nil, err
-	}
-	upgrader := GoUpgrader(env, jUpgrader)
 	resolverSign := jutil.ClassSign("io.v.v23.syncbase.nosql.ConflictResolver")
 	jResolver, err := jutil.CallObjectMethod(env, jSchema, "getResolver", nil, resolverSign)
 	if err != nil {
@@ -84,7 +78,6 @@
 	resolver := GoResolver(env, jResolver)
 	return &nosql.Schema{
 		Metadata: metadata,
-		Upgrader: upgrader,
 		Resolver: resolver,
 	}, nil
 }