WebSQL: Add missing getExecutionContext() null check

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 833 matching lines @@
     SQLTransactionErrorCallback* callback,
     std::unique_ptr<SQLErrorData> errorData) {
   callback->handleEvent(SQLError::create(*errorData));
 }
 
 void Database::runTransaction(SQLTransactionCallback* callback,
                               SQLTransactionErrorCallback* errorCallback,
                               VoidCallback* successCallback,
                               bool readOnly,
                               const ChangeVersionData* changeVersionData) {
+  if (!getExecutionContext())
+    return;
+
   ASSERT(getExecutionContext()->isContextThread());
 // FIXME: Rather than passing errorCallback to SQLTransaction and then
 // sometimes firing it ourselves, this code should probably be pushed down
 // into Database so that we only create the SQLTransaction if we're
 // actually going to run it.
 #if ENABLE(ASSERT)
   SQLTransactionErrorCallback* originalErrorCallback = errorCallback;
 #endif
   SQLTransaction* transaction = SQLTransaction::create(
       this, callback, successCallback, errorCallback, readOnly);
@@ skipping 77 matching lines @@
   if (getDatabaseContext()->databaseThread()->isDatabaseThread())
     return m_databaseThreadSecurityOrigin.get();
   return nullptr;
 }
 
 bool Database::opened() {
   return static_cast<bool>(acquireLoad(&m_opened));
 }
 
 }  // namespace blink