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

chrome/browser/sync/engine/syncapi_internal.cc

Index: chrome/browser/sync/engine/syncapi_internal.cc
diff --git a/chrome/browser/sync/engine/syncapi_internal.cc b/chrome/browser/sync/engine/syncapi_internal.cc
index 3db0ea811476f2a85d308444812cbff3c15c8c06..8bd5c1d7c53e2c3a55c45078ee85b02dce662575 100644
--- a/chrome/browser/sync/engine/syncapi_internal.cc
+++ b/chrome/browser/sync/engine/syncapi_internal.cc
@@ -7,6 +7,7 @@
 #include "base/memory/scoped_ptr.h"
 #include "chrome/browser/sync/util/cryptographer.h"
 #include "chrome/browser/sync/protocol/password_specifics.pb.h"
+#include "chrome/browser/sync/protocol/sync.pb.h"
 
 using browser_sync::Cryptographer;
 
@@ -14,10 +15,9 @@ namespace sync_api {
 
 sync_pb::PasswordSpecificsData* DecryptPasswordSpecifics(
     const sync_pb::EntitySpecifics& specifics, Cryptographer* crypto) {
-  if (!specifics.HasExtension(sync_pb::password))
+  if (!specifics.has_password())
     return NULL;
-  const sync_pb::PasswordSpecifics& password_specifics =
-      specifics.GetExtension(sync_pb::password);
+  const sync_pb::PasswordSpecifics& password_specifics = specifics.password();
   if (!password_specifics.has_encrypted())
     return NULL;
   const sync_pb::EncryptedData& encrypted = password_specifics.encrypted();