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

chrome/browser/extensions/settings/setting_sync_data.cc

 // Copyright (c) 2011 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/extensions/settings/setting_sync_data.h"
 
 #include "base/json/json_reader.h"
 #include "base/json/json_writer.h"
 #include "chrome/browser/sync/api/sync_data.h"
 #include "chrome/browser/sync/protocol/extension_setting_specifics.pb.h"
+#include "chrome/browser/sync/protocol/sync.pb.h"
 
 namespace extensions {
 
 SettingSyncData::SettingSyncData(
     const SyncChange& sync_change) {
   Init(sync_change.change_type(), sync_change.sync_data());
 }
 
 SettingSyncData::SettingSyncData(
     const SyncData& sync_data) {
   Init(SyncChange::ACTION_INVALID, sync_data);
 }
 
 void SettingSyncData::Init(
     SyncChange::SyncChangeType change_type, const SyncData& sync_data) {
   DCHECK(!internal_.get());
   sync_pb::ExtensionSettingSpecifics specifics =
-      sync_data.GetSpecifics().GetExtension(sync_pb::extension_setting);
+      sync_data.GetSpecifics().extension_setting();
   Value* value =
       base::JSONReader().JsonToValue(specifics.value(), false, false);
   if (!value) {
     LOG(WARNING) << "Specifics for " << specifics.extension_id() << "/" <<
         specifics.key() << " had bad JSON for value: " << specifics.value();
     value = new DictionaryValue();
   }
   internal_ = new Internal(
       change_type,
       specifics.extension_id(),
@@ skipping 34 matching lines @@
     const std::string& key,
     Value* value)
     : change_type_(change_type),
       extension_id_(extension_id),
       key_(key),
       value_(value) {}
 
 SettingSyncData::Internal::~Internal() {}
 
 }  // namespace extensions