Revert of Set the request mode and the credentials mode of FetchEvent in the service worker correctly.

third_party/WebKit/Source/platform/network/ResourceRequest.cpp

 /*
  * Copyright (C) 2003, 2006 Apple Computer, Inc.  All rights reserved.
  * Copyright (C) 2009, 2012 Google 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
@@ skipping 411 matching lines @@
     m_skipServiceWorker = false;
     m_shouldResetAppCache = false;
     m_priority = ResourceLoadPriorityLowest;
     m_intraPriorityValue = 0;
     m_requestorID = 0;
     m_requestorProcessID = 0;
     m_appCacheHostID = 0;
     m_requestContext = WebURLRequest::RequestContextUnspecified;
     m_frameType = WebURLRequest::FrameTypeNone;
     m_fetchRequestMode = WebURLRequest::FetchRequestModeNoCORS;
-    m_fetchCredentialsMode = WebURLRequest::FetchCredentialsModeInclude;
+    // Contrary to the Fetch spec, we default to same-origin mode here, and deal
+    // with CORS modes in updateRequestForAccessControl if we're called in a
+    // context which requires it.
+    m_fetchCredentialsMode = WebURLRequest::FetchCredentialsModeSameOrigin;
     m_fetchRedirectMode = WebURLRequest::FetchRedirectModeFollow;
     m_referrerPolicy = ReferrerPolicyDefault;
     m_loFiState = WebURLRequest::LoFiUnspecified;
     m_didSetHTTPReferrer = false;
     m_checkForBrowserSideNavigation = true;
     m_uiStartTime = 0;
     m_originatesFromReservedIPRange = false;
     m_inputPerfMetricReportPolicy = InputToLoadPerfMetricReportPolicy::NoReport;
     m_followedRedirect = false;
     m_requestorOrigin = SecurityOrigin::createUnique();
 }
 
 } // namespace blink