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 e4caac40bb90dc83ab950f47f4609b065ff58444..c102e185afa525f1eacc0559ece7d0e3d0828c81 100644
--- a/third_party/WebKit/Source/core/xmlhttprequest/XMLHttpRequest.cpp
+++ b/third_party/WebKit/Source/core/xmlhttprequest/XMLHttpRequest.cpp
@@ -1365,7 +1365,7 @@ void XMLHttpRequest::didFail(const ResourceError& error)
     if (m_error)
         return;
 
-    if (error.isCancellation()) {
+    if (error.isCancellation() && !error.isAccessCheck()) {
         handleDidCancel();
         return;
     }