[XHR] Add CHECK to make sure XHR::m_loader is not silently released

third_party/WebKit/Source/core/xmlhttprequest/XMLHttpRequest.cpp

 /*
  *  Copyright (C) 2004, 2006, 2008 Apple Inc. All rights reserved.
  *  Copyright (C) 2005-2007 Alexey Proskuryakov <ap@webkit.org>
  *  Copyright (C) 2007, 2008 Julien Chaffraix <jchaffraix@webkit.org>
  *  Copyright (C) 2008, 2011 Google Inc. All rights reserved.
  *  Copyright (C) 2012 Intel Corporation
  *
  *  This library is free software; you can redistribute it and/or
  *  modify it under the terms of the GNU Lesser General Public
  *  License as published by the Free Software Foundation; either
@@ skipping 1023 matching lines @@
 
   m_exceptionCode = 0;
   m_error = false;
 
   if (m_async) {
     UseCounter::count(&executionContext,
                       UseCounter::XMLHttpRequestAsynchronous);
     if (m_upload)
       request.setReportUploadProgress(true);
 
-    DCHECK(!m_loader);
+    // TODO(yhirano): Turn this CHECK into DCHECK once https://crbug.com/667254
+    // is fixed.
+    CHECK(!m_loader);
     DCHECK(m_sendFlag);
     m_loader = ThreadableLoader::create(executionContext, this, options,
                                         resourceLoaderOptions);
     m_loader->start(request);
 
     return;
   }
 
+  // TODO(yhirano): Remove this CHECK once https://crbug.com/667254 is fixed.
+  CHECK(!m_loader);
   // Use count for XHR synchronous requests.
   UseCounter::count(&executionContext, UseCounter::XMLHttpRequestSynchronous);
   ThreadableLoader::loadResourceSynchronously(executionContext, request, *this,
                                               options, resourceLoaderOptions);
 
   throwForLoadFailureIfNeeded(exceptionState, String());
 }
 
 void XMLHttpRequest::abort() {
   NETWORK_DVLOG(1) << this << " abort()";
@@ skipping 780 matching lines @@
   visitor->traceWrappers(m_responseDocument);
   visitor->traceWrappers(m_responseArrayBuffer);
   XMLHttpRequestEventTarget::traceWrappers(visitor);
 }
 
 std::ostream& operator<<(std::ostream& ostream, const XMLHttpRequest* xhr) {
   return ostream << "XMLHttpRequest " << static_cast<const void*>(xhr);
 }
 
 }  // namespace blink