Switched sync protobufs to use "heavy" protobufs.

chrome/browser/sync/protocol/autofill_specifics.proto

 // Copyright (c) 2010 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.
 //
 // Sync protocol datatype extension for autofill.
 
 syntax = "proto2";
 
-option optimize_for = LITE_RUNTIME;
+// TODO(akalin): Re-enable this once LITE_RUNTIME supports preserving
+// unknown fields.
+
+// option optimize_for = LITE_RUNTIME;
 
 package sync_pb;
 
 import "sync.proto";
 
 // Properties of autofill sync objects.
 
 // An AutofillProfile.
 message AutofillProfileSpecifics {
   // User-defined label.
@@ skipping 67 matching lines @@
   optional bytes encrypted_credit_card = 5;
 
   // If encryption for autofill++ is not enabled, this field stores the
   // AutofillCreditCardSpecifics [instead of |encrypted_credit_card|].
   optional AutofillCreditCardSpecifics credit_card = 6;
 }
 
 extend EntitySpecifics {
   optional AutofillSpecifics autofill = 31729;
 }