sync: Implement disabling of non blocking types

sync/internal_api/test/null_sync_core_proxy.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "sync/internal_api/public/test/null_sync_core_proxy.h"
 
 namespace syncer {
 
 NullSyncCoreProxy::NullSyncCoreProxy() {}
 
 NullSyncCoreProxy::~NullSyncCoreProxy() {}
 
 void NullSyncCoreProxy::ConnectTypeToCore(
     syncer::ModelType type,
       base::WeakPtr<NonBlockingTypeProcessor> processor) {
   NOTREACHED() << "NullSyncCoreProxy is not meant to be used";
 }
 
+void NullSyncCoreProxy::Disconnect(syncer::ModelType type) {
+  NOTREACHED() << "NullSyncCoreProxy is not meant to be used";
+}
+
 scoped_ptr<SyncCoreProxy> NullSyncCoreProxy::Clone() const {
   return scoped_ptr<SyncCoreProxy>(new NullSyncCoreProxy());
 }
 
 }  // namespace syncer