Replace WTF::emptyString{16Bit}() with a static global

third_party/WebKit/Source/modules/webdatabase/Database.cpp

 /*
  * Copyright (C) 2013 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 442 matching lines @@
   m_sqliteDatabase.setBusyTimeout(maxSqliteBusyWaitTime);
 
   String currentVersion;
   {
     SafePointAwareMutexLocker locker(guidMutex());
 
     GuidVersionMap::iterator entry = guidToVersionMap().find(m_guid);
     if (entry != guidToVersionMap().end()) {
       // Map null string to empty string (see updateGuidVersionMap()).
       currentVersion =
-          entry->value.isNull() ? emptyString() : entry->value.isolatedCopy();
+          entry->value.isNull() ? emptyString : entry->value.isolatedCopy();
       STORAGE_DVLOG(1) << "Current cached version for guid " << m_guid << " is "
                        << currentVersion;
 
       // Note: In multi-process browsers the cached value may be
       // inaccurate, but we cannot read the actual version from the
       // database without potentially inducing a form of deadlock, a
       // busytimeout error when trying to access the database. So we'll
       // use the cached value if we're unable to read the value from the
       // database file without waiting.
       // FIXME: Add an async openDatabase method to the DatabaseAPI.
@@ skipping 472 matching lines @@
   if (getDatabaseContext()->databaseThread()->isDatabaseThread())
     return m_databaseThreadSecurityOrigin.get();
   return nullptr;
 }
 
 bool Database::opened() {
   return static_cast<bool>(acquireLoad(&m_opened));
 }
 
 }  // namespace blink