Remove duplicated code from sync related unit tests.

sync/api/fake_sync_change_processor.cc

 // Copyright 2013 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/api/fake_sync_change_processor.h"
+#include "sync/api/sync_change.h"
+#include "sync/api/sync_data.h"
 
 namespace syncer {
 
 FakeSyncChangeProcessor::FakeSyncChangeProcessor() {}
 
 FakeSyncChangeProcessor::~FakeSyncChangeProcessor() {}
 
 syncer::SyncError FakeSyncChangeProcessor::ProcessSyncChanges(
       const tracked_objects::Location& from_here,
       const syncer::SyncChangeList& change_list) {
+  change_list_.insert(
+      change_list_.end(), change_list.begin(), change_list.end());
   return syncer::SyncError();
 }
 
 syncer::SyncDataList FakeSyncChangeProcessor::GetAllSyncData(
     syncer::ModelType type) const {
   return syncer::SyncDataList();
 }
 
+const syncer::SyncChangeList& FakeSyncChangeProcessor::changes() const {
+  return change_list_;
+}
+
+syncer::SyncChangeList& FakeSyncChangeProcessor::changes() {
+  return change_list_;
+}
+
 }  // namespace syncer