Remove duplicated code from sync related unit tests.

sync/api/sync_change_processor_wrapper_for_test.h

+// 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.
+
+#ifndef SYNC_API_SYNC_CHANGE_PROCESSOR_WRAPPER_FOR_TEST_H_
+#define SYNC_API_SYNC_CHANGE_PROCESSOR_WRAPPER_FOR_TEST_H_
+
+#include "sync/api/sync_change_processor.h"
+
+namespace syncer {
+
+// A wrapper class for use in tests.
+class SyncChangeProcessorWrapperForTest : public SyncChangeProcessor {
+ public:
+  // Create a SyncChangeProcessorWrapperForTest.
+  //
+  // All method calls are forwarded to |wrapped|. Caller maintains ownership
+  // of |wrapped| and is responsible for ensuring it outlives this object.
+  explicit SyncChangeProcessorWrapperForTest(
+      syncer::SyncChangeProcessor* wrapped);
+  virtual ~SyncChangeProcessorWrapperForTest();
+
+  // SyncChangeProcessor implementation.
+  virtual syncer::SyncError ProcessSyncChanges(
+      const tracked_objects::Location& from_here,
+      const syncer::SyncChangeList& change_list) OVERRIDE;
+  virtual syncer::SyncDataList GetAllSyncData(syncer::ModelType type)
+      const OVERRIDE;
+
+ private:
+  syncer::SyncChangeProcessor* const wrapped_;
+
+  DISALLOW_COPY_AND_ASSIGN(SyncChangeProcessorWrapperForTest);
+};
+
+}  // namespace syncer
+
+#endif  // SYNC_API_SYNC_CHANGE_PROCESSOR_WRAPPER_FOR_TEST_H_