[Sync] Make SMTP always have the dump stack function.

chrome/browser/sync/test/integration/two_client_uss_sync_test.cc

 // Copyright 2016 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 "base/macros.h"
 #include "base/memory/ptr_util.h"
 #include "base/optional.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "chrome/browser/sync/chrome_sync_client.h"
 #include "chrome/browser/sync/profile_sync_service_factory.h"
@@ skipping 46 matching lines @@
 
 // A FakeModelTypeSyncBridge that supports observing ApplySyncChanges.
 class TestModelTypeSyncBridge : public FakeModelTypeSyncBridge {
  public:
   class Observer {
    public:
     virtual void OnApplySyncChanges() = 0;
   };
 
   TestModelTypeSyncBridge()
-      : FakeModelTypeSyncBridge(base::Bind(&ModelTypeChangeProcessor::Create)) {
+      : FakeModelTypeSyncBridge(base::Bind(&ModelTypeChangeProcessor::Create,
+                                           base::RepeatingClosure())) {
     change_processor()->ModelReadyToSync(db().CreateMetadataBatch());
   }
 
   base::Optional<syncer::ModelError> ApplySyncChanges(
       std::unique_ptr<syncer::MetadataChangeList> metadata_changes,
       syncer::EntityChangeList entity_changes) override {
     auto error = FakeModelTypeSyncBridge::ApplySyncChanges(
         std::move(metadata_changes), entity_changes);
     NotifyObservers();
     return error;
@@ skipping 284 matching lines @@
 
   ASSERT_TRUE(DataChecker(model1, kKey1, kValue2).Wait());
   ASSERT_TRUE(DataChecker(model1, kKey2, kValue1).Wait());
   ASSERT_TRUE(DataChecker(model1, kKey4, kValue1).Wait());
 
   ASSERT_TRUE(DataChecker(model0, kKey1, kValue2).Wait());
   ASSERT_TRUE(DataChecker(model0, kKey3, kValue1).Wait());
 }
 
 }  // namespace