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

chrome/browser/sync/engine/conflict_resolver.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/conflict_resolver.h"
 
 #include <algorithm>
 #include <list>
 #include <map>
 #include <set>
@@ skipping 211 matching lines @@
       if (decrypted_server_specifics == decrypted_base_server_specifics)
           base_server_specifics_match = true;
     }
 
     // We manually merge nigori data.
     if (entry.GetModelType() == syncable::NIGORI) {
       // Create a new set of specifics based on the server specifics (which
       // preserves their encryption keys).
       sync_pb::EntitySpecifics specifics =
           entry.Get(syncable::SERVER_SPECIFICS);
-      sync_pb::NigoriSpecifics* nigori =
-          specifics.MutableExtension(sync_pb::nigori);
+      sync_pb::NigoriSpecifics* server_nigori = specifics.mutable_nigori();
       // Store the merged set of encrypted types (cryptographer->Update(..) will
       // have merged the local types already).
-      cryptographer->UpdateNigoriFromEncryptedTypes(nigori);
+      cryptographer->UpdateNigoriFromEncryptedTypes(server_nigori);
       // The local set of keys is already merged with the server's set within
       // the cryptographer. If we don't have pending keys we can store the
       // merged set back immediately. Else we preserve the server keys and will
       // update the nigori when the user provides the pending passphrase via
       // SetPassphrase(..).
       if (cryptographer->is_ready()) {
-        cryptographer->GetKeys(nigori->mutable_encrypted());
+        cryptographer->GetKeys(server_nigori->mutable_encrypted());
       }
       // TODO(zea): Find a better way of doing this. As it stands, we have to
       // update this code whenever we add a new non-cryptographer related field
       // to the nigori node.
-      if (entry.Get(syncable::SPECIFICS).GetExtension(sync_pb::nigori)
-              .sync_tabs()) {
-        nigori->set_sync_tabs(true);
+      if (entry.Get(syncable::SPECIFICS).nigori().sync_tabs()) {
+        server_nigori->set_sync_tabs(true);
       }
       // We deliberately leave the server's device information. This client will
       // add it's own device information on restart.
       entry.Put(syncable::SPECIFICS, specifics);
       DVLOG(1) << "Resovling simple conflict, merging nigori nodes: " << entry;
       status->increment_num_server_overwrites();
       OverwriteServerChanges(trans, &entry);
       UMA_HISTOGRAM_ENUMERATION("Sync.ResolveSimpleConflict",
                                 NIGORI_MERGE,
                                 CONFLICT_RESOLUTION_SIZE);
@@ skipping 138 matching lines @@
           forward_progress = true;
           break;
       }
       processed_items.insert(id);
     }
   }
   return forward_progress;
 }
 
 }  // namespace browser_sync