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

chrome/browser/sync/profile_sync_service_preference_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 <map>
 #include <string>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/callback.h"
@@ skipping 158 matching lines @@
 
   // Caller gets ownership of the returned value.
   const Value* GetSyncedValue(const std::string& name) {
     sync_api::ReadTransaction trans(FROM_HERE, service_->GetUserShare());
     sync_api::ReadNode node(&trans);
 
     if (!node.InitByClientTagLookup(syncable::PREFERENCES, name))
       return NULL;
 
     const sync_pb::PreferenceSpecifics& specifics(
-        node.GetEntitySpecifics().GetExtension(sync_pb::preference));
+        node.GetEntitySpecifics().preference());
 
     JSONReader reader;
     return reader.JsonToValue(specifics.value(), false, false);
   }
 
   int64 WriteSyncedValue(const std::string& name,
                          const Value& value,
                          sync_api::WriteNode* node) {
     SyncData sync_data;
     if (!PrefModelAssociator::CreatePrefSyncData(name,
@@ skipping 70 matching lines @@
   ASSERT_TRUE(StartSyncService(create_root.callback(), false));
   ASSERT_TRUE(create_root.success());
 
   const PrefService::Preference* pref =
       prefs_->FindPreference(prefs::kHomePage);
   SyncData sync_data;
   EXPECT_TRUE(PrefModelAssociator::CreatePrefSyncData(pref->name(),
       *pref->GetValue(), &sync_data));
   EXPECT_EQ(std::string(prefs::kHomePage), sync_data.GetTag());
   const sync_pb::PreferenceSpecifics& specifics(sync_data.GetSpecifics().
-      GetExtension(sync_pb::preference));
+      preference());
   EXPECT_EQ(std::string(prefs::kHomePage), specifics.name());
 
   base::JSONReader reader;
   scoped_ptr<Value> value(reader.JsonToValue(specifics.value(), false, false));
   EXPECT_TRUE(pref->GetValue()->Equals(value.get()));
 }
 
 TEST_F(ProfileSyncServicePreferenceTest, ModelAssociationDoNotSyncDefaults) {
   const PrefService::Preference* pref =
       prefs_->FindPreference(prefs::kHomePage);
@@ skipping 304 matching lines @@
   EXPECT_FALSE(pref->IsDefaultValue());
   // There should be no synced value.
   EXPECT_TRUE(GetSyncedValue(prefs::kHomePage) == NULL);
   // Switch kHomePage back to unmanaged.
   profile_->GetTestingPrefService()->RemoveManagedPref(prefs::kHomePage);
   // The original value should be picked up.
   EXPECT_TRUE(pref->IsDefaultValue());
   // There should still be no synced value.
   EXPECT_TRUE(GetSyncedValue(prefs::kHomePage) == NULL);
 }