Fix a race in DatabaseManager::manager.

Source/modules/webdatabase/DatabaseManager.cpp

 /*
  * Copyright (C) 2012 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 31 matching lines @@
 #include "modules/webdatabase/DatabaseContext.h"
 #include "modules/webdatabase/DatabaseServer.h"
 #include "modules/webdatabase/DatabaseSync.h"
 #include "modules/webdatabase/DatabaseTask.h"
 #include "platform/weborigin/SecurityOrigin.h"
 
 namespace WebCore {
 
 DatabaseManager& DatabaseManager::manager()
 {
-    static DatabaseManager* dbManager = 0;
-    // FIXME: The following is vulnerable to a race between threads. Need to
-    // implement a thread safe on-first-use static initializer.
-    if (!dbManager)
-        dbManager = new DatabaseManager();
-
+    AtomicallyInitializedStatic(DatabaseManager*, dbManager = new DatabaseManager);

[eseidel, 2014/05/29 07:03:37]

I didn't know this existed, crazy.

https://code.google.com/p/chromium/codesearch#chromium/src/third_party/WebKit...

     return *dbManager;
 }
 
 DatabaseManager::DatabaseManager()
 #if !ASSERT_DISABLED
     : m_databaseContextRegisteredCount(0)
     , m_databaseContextInstanceCount(0)
 #endif
 {
     m_server = new DatabaseServer;
@@ skipping 210 matching lines @@
 {
     m_server->interruptAllDatabasesForContext(databaseContext->backend());
 }
 
 void DatabaseManager::logErrorMessage(ExecutionContext* context, const String& message)
 {
     context->addConsoleMessage(StorageMessageSource, ErrorMessageLevel, message);
 }
 
 } // namespace WebCore