Show better CORS error message when status code is not set

Source/core/fetch/CrossOriginAccessControl.cpp

 /*
  * Copyright (C) 2008 Apple 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
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 125 matching lines @@
 static bool isOriginSeparator(UChar ch)
 {
     return isASCIISpace(ch) || ch == ',';
 }
 
 bool passesAccessControlCheck(const ResourceResponse& response, StoredCredentials includeCredentials, SecurityOrigin* securityOrigin, String& errorDescription)
 {
     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);
     if (accessControlOriginString == starAtom && includeCredentials == DoNotAllowStoredCredentials)
         return true;
 
     if (accessControlOriginString != securityOrigin->toAtomicString()) {
         if (accessControlOriginString == starAtom) {
             errorDescription = "A wildcard '*' cannot be used in the 'Access-Control-Allow-Origin' header when the credentials flag is true. Origin '" + securityOrigin->toString() + "' is therefore not allowed access.";
         } else if (accessControlOriginString.isEmpty()) {
@@ skipping 36 matching lines @@
     Vector<String> headers;
     headerValue.split(',', false, headers);
     for (unsigned headerCount = 0; headerCount < headers.size(); headerCount++) {
         String strippedHeader = headers[headerCount].stripWhiteSpace();
         if (!strippedHeader.isEmpty())
             headerSet.add(strippedHeader);
     }
 }
 
 } // namespace WebCore