sync: remove use of protobuf extensions in protocol to reduce static init overhead.

chrome/browser/sync/engine/process_commit_response_command_unittest.cc

 // 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.
 
 #include <vector>
 
 #include "base/location.h"
 #include "base/stringprintf.h"
 #include "chrome/browser/sync/engine/process_commit_response_command.h"
 #include "chrome/browser/sync/protocol/bookmark_specifics.pb.h"
@@ skipping 79 matching lines @@
     ASSERT_TRUE(entry.good());
     entry.Put(syncable::ID, item_id);
     entry.Put(syncable::BASE_VERSION,
         item_id.ServerKnows() ? next_old_revision_++ : 0);
     entry.Put(syncable::IS_UNSYNCED, true);
     entry.Put(syncable::IS_DIR, is_folder);
     entry.Put(syncable::IS_DEL, false);
     entry.Put(syncable::PARENT_ID, parent_id);
     entry.PutPredecessor(predecessor_id);
     sync_pb::EntitySpecifics default_specifics;
-    syncable::AddDefaultExtensionValue(model_type, &default_specifics);
+    syncable::AddDefaultFieldValue(model_type, &default_specifics);
     entry.Put(syncable::SPECIFICS, default_specifics);
     if (item_id.ServerKnows()) {
       entry.Put(syncable::SERVER_SPECIFICS, default_specifics);
       entry.Put(syncable::SERVER_IS_DIR, is_folder);
       entry.Put(syncable::SERVER_PARENT_ID, parent_id);
       entry.Put(syncable::SERVER_IS_DEL, false);
     }
     if (metahandle_out)
       *metahandle_out = entry.Get(syncable::META_HANDLE);
   }
@@ skipping 317 matching lines @@
     EXPECT_EQ("xyz", final_monitor_records["xyz"].extension_id);
     EXPECT_EQ(2049U, final_monitor_records["ABC"].bookmark_write_count);
     EXPECT_EQ(4U,    final_monitor_records["xyz"].bookmark_write_count);
   } else {
     EXPECT_TRUE(final_monitor_records.empty())
         << "Should not restore records after successful bookmark commit.";
   }
 }
 
 }  // namespace browser_sync