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

chrome/browser/sync/engine/download_updates_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 "chrome/browser/sync/engine/download_updates_command.h"
 #include "chrome/browser/sync/protocol/autofill_specifics.pb.h"
 #include "chrome/browser/sync/protocol/bookmark_specifics.pb.h"
 #include "chrome/browser/sync/protocol/preference_specifics.pb.h"
 #include "chrome/browser/sync/protocol/sync.pb.h"
 #include "chrome/browser/sync/test/engine/fake_model_worker.h"
-#include "chrome/browser/sync/test/engine/proto_extension_validator.h"
 #include "chrome/browser/sync/test/engine/syncer_command_test.h"
 
 using ::testing::_;
 namespace browser_sync {
 
 using syncable::FIRST_REAL_MODEL_TYPE;
 using syncable::MODEL_TYPE_COUNT;
 
 // A test fixture for tests exercising DownloadUpdatesCommandTest.
 class DownloadUpdatesCommandTest : public SyncerCommandTest {
@@ skipping 44 matching lines @@
   EXPECT_CALL(*(mock_debug_info_getter()), GetAndClearDebugInfo(_))
       .Times(1);
   command_.AppendClientDebugInfoIfNeeded(session(), &debug_info);
 
   // Now try to add it once more and make sure |GetAndClearDebugInfo| is not
   // called.
   command_.AppendClientDebugInfoIfNeeded(session(), &debug_info);
 }
 
 }  // namespace browser_sync