Revert of Make ResourceFetcher return Resources with LoadError instead of nullptrs.

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

Index: third_party/WebKit/Source/core/xmlhttprequest/XMLHttpRequest.cpp
diff --git a/third_party/WebKit/Source/core/xmlhttprequest/XMLHttpRequest.cpp b/third_party/WebKit/Source/core/xmlhttprequest/XMLHttpRequest.cpp
index 91188b57fbf107336e00b9d22827900354745acf..b9cf5ab7b43f3fe65ffcb5186ca8893d8ebabe1c 100644
--- a/third_party/WebKit/Source/core/xmlhttprequest/XMLHttpRequest.cpp
+++ b/third_party/WebKit/Source/core/xmlhttprequest/XMLHttpRequest.cpp
@@ -1468,12 +1468,7 @@
   if (m_error)
     return;
 
-  // Internally, access check violations are considered `cancellations`, but
-  // at least the mixed-content and CSP specs require them to be surfaced as
-  // network errors to the page. See:
-  //   [1] https://www.w3.org/TR/mixed-content/#algorithms,
-  //   [2] https://www.w3.org/TR/CSP3/#fetch-integration.
-  if (error.isCancellation() && !error.isAccessCheck()) {
+  if (error.isCancellation()) {
     handleDidCancel();
     return;
   }