Show better CORS error message when status code is not set

Source/core/fetch/CrossOriginAccessControl.cpp

Index: Source/core/fetch/CrossOriginAccessControl.cpp
diff --git a/Source/core/fetch/CrossOriginAccessControl.cpp b/Source/core/fetch/CrossOriginAccessControl.cpp
index 33a60d0ae78ebceab697275e4e97fdd959c3f6ff..d2a87bf2abb80e348a9c74a42f1098733e7c9d46 100644
--- a/Source/core/fetch/CrossOriginAccessControl.cpp
+++ b/Source/core/fetch/CrossOriginAccessControl.cpp
@@ -143,6 +143,11 @@ bool passesAccessControlCheck(const ResourceResponse& response, StoredCredential
     AtomicallyInitializedStatic(AtomicString&, accessControlAllowOrigin = *new AtomicString("access-control-allow-origin", AtomicString::ConstructFromLiteral));
     AtomicallyInitializedStatic(AtomicString&, accessControlAllowCredentials = *new AtomicString("access-control-allow-credentials", AtomicString::ConstructFromLiteral));
 
+    if (!response.httpStatusCode()) {
+        errorDescription = "Received an invalid response. Origin '" + securityOrigin->toString() + "' is therefore not allowed access.";
+        return false;
+    }
+
     // A wildcard Access-Control-Allow-Origin can not be used if credentials are to be sent,
     // even with Access-Control-Allow-Credentials set to true.
     const AtomicString& accessControlOriginString = response.httpHeaderField(accessControlAllowOrigin);