Move StringToLowerASCII to base namespace

sync/internal_api/public/base/attachment_id_proto.cc

 // Copyright 2014 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 "sync/internal_api/public/base/attachment_id_proto.h"
 
 #include "base/guid.h"
 #include "base/logging.h"
 #include "base/strings/string_util.h"
 
 namespace syncer {
 
 sync_pb::AttachmentIdProto CreateAttachmentIdProto() {
   sync_pb::AttachmentIdProto proto;
-  std::string guid = StringToLowerASCII(base::GenerateGUID());
+  std::string guid = base::StringToLowerASCII(base::GenerateGUID());
   DCHECK(!guid.empty());
   // Requirements are that this id must be a unique RFC4122 UUID, formatted in
   // lower case.
   proto.set_unique_id(guid);
   return proto;
 }
 
 sync_pb::AttachmentMetadata CreateAttachmentMetadata(
     const google::protobuf::RepeatedPtrField<sync_pb::AttachmentIdProto>& ids) {
   sync_pb::AttachmentMetadata result;
   for (int i = 0; i < ids.size(); ++i) {
     sync_pb::AttachmentMetadataRecord* record = result.add_record();
     *record->mutable_id() = ids.Get(i);
     record->set_is_on_server(true);
   }
   return result;
 }
 
 }  // namespace syncer