Consider "mixed content XHR" as mixed script instead of mixed display.

Source/core/xml/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 730 matching lines @@
     ThreadableLoaderOptions options;
     options.sendLoadCallbacks = SendCallbacks;
     options.sniffContent = DoNotSniffContent;
     options.preflightPolicy = uploadEvents ? ForcePreflight : ConsiderPreflight;
     options.allowCredentials = (m_sameOriginRequest || m_includeCredentials) ? AllowStoredCredentials : DoNotAllowStoredCredentials;
     options.credentialsRequested = m_includeCredentials ? ClientRequestedCredentials : ClientDidNotRequestCredentials;
     options.crossOriginRequestPolicy = m_allowCrossOriginRequests ? AllowCrossOriginRequests : UseAccessControl;
     options.securityOrigin = securityOrigin();
     options.initiator = FetchInitiatorTypeNames::xmlhttprequest;
     options.contentSecurityPolicyEnforcement = ContentSecurityPolicy::shouldBypassMainWorld(scriptExecutionContext()) ? DoNotEnforceContentSecurityPolicy : EnforceConnectSrcDirective;
+    options.mixedContentBlockingTreatment = TreatAsActiveContent;
     options.timeoutMilliseconds = m_timeoutMilliseconds;
 
     m_exceptionCode = 0;
     m_error = false;
 
     if (m_async) {
         if (m_upload)
             request.setReportUploadProgress(true);
 
         // ThreadableLoader::create can return null here, for example if we're no longer attached to a page.
@@ skipping 496 matching lines @@
 {
     return eventNames().interfaceForXMLHttpRequest;
 }
 
 ScriptExecutionContext* XMLHttpRequest::scriptExecutionContext() const
 {
     return ActiveDOMObject::scriptExecutionContext();
 }
 
 } // namespace WebCore