Rewrite std::string("") to std::string(), Linux edition.

sync/syncable/directory_backing_store.cc

 // Copyright 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 "sync/syncable/directory_backing_store.h"
 
 #include "build/build_config.h"
 
 #include <limits>
 
@@ skipping 1251 matching lines @@
             "?, "   // store_birthday
             "?, "   // db_create_version
             "?, "   // db_create_time
             "-2, "  // next_id
             "?, "   // cache_guid
             // TODO(rlarocque, 124140): Remove notification_state field.
             "?, "   // notification_state
             "?);"));  // bag_of_chips
     s.BindString(0, dir_name_);                   // id
     s.BindString(1, dir_name_);                   // name
-    s.BindString(2, "");                          // store_birthday
+    s.BindString(2, std::string());               // store_birthday
     // TODO(akalin): Remove this unused db_create_version field. (Or
     // actually use it for something.) http://crbug.com/118356
     s.BindString(3, "Unknown");                   // db_create_version
     s.BindInt(4, static_cast<int32>(time(0)));    // db_create_time
     s.BindString(5, GenerateCacheGUID());         // cache_guid
     // TODO(rlarocque, 124140): Remove this unused notification-state field.
     s.BindBlob(6, NULL, 0);                       // notification_state
     s.BindBlob(7, NULL, 0);                       // bag_of_chips
     if (!s.Run())
       return false;
@@ skipping 197 matching lines @@
   }
   query.append(" ) ");
   values.append(" )");
   query.append(values);
   save_statement->Assign(db_->GetUniqueStatement(
       base::StringPrintf(query.c_str(), "metas").c_str()));
 }
 
 }  // namespace syncable
 }  // namespace syncer