[Sync] Add tests for invalid specifics field number handling

sync/internal_api/public/base/model_type.h

 // Copyright (c) 2012 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.
 
 // Enumerate the various item subtypes that are supported by sync.
 // Each sync object is expected to have an immutable object type.
 // An object's type is inferred from the type of data it holds.
 
 #ifndef SYNC_INTERNAL_API_PUBLIC_BASE_MODEL_TYPE_H_
 #define SYNC_INTERNAL_API_PUBLIC_BASE_MODEL_TYPE_H_
@@ skipping 156 matching lines @@
 // following pattern:
 //
 //   ModelTypeSet model_types;
 //   // Say we're looping through a list of items, each of which has a
 //   // field number.
 //   for (...) {
 //     int field_number = ...;
 //     ModelType model_type =
 //         GetModelTypeFromSpecificsFieldNumber(field_number);
 //     if (!IsRealDataType(model_type)) {
-//       NOTREACHED() << "Unknown field number " << field_number;
+//       DLOG(WARNING) << "Unknown field number " << field_number;
 //       continue;
 //     }
 //     model_types.Put(model_type);
 //   }
 ModelType GetModelTypeFromSpecificsFieldNumber(int field_number);
 
 // Return the field number of the EntitySpecifics field associated with
 // a model type.
 //
 // Used by tests outside of sync.
@@ skipping 42 matching lines @@
 // type and |model_type| was filled in.
 bool NotificationTypeToRealModelType(const std::string& notification_type,
                                      ModelType* model_type);
 
 // Returns true if |model_type| is a real datatype
 SYNC_EXPORT bool IsRealDataType(ModelType model_type);
 
 }  // namespace syncer
 
 #endif  // SYNC_INTERNAL_API_PUBLIC_BASE_MODEL_TYPE_H_