Correctly resolve empty script URLs in Worker constructors.

Source/core/workers/AbstractWorker.cpp

 /*
  * Copyright (C) 2010 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 33 matching lines @@
     : ActiveDOMObject(context)
 {
 }
 
 AbstractWorker::~AbstractWorker()
 {
 }
 
 KURL AbstractWorker::resolveURL(const String& url, ExceptionState& exceptionState)
 {
-    if (url.isEmpty()) {
-        exceptionState.throwDOMException(SyntaxError, "Failed to create a worker: an empty URL was provided.");
-        return KURL();
-    }
-
     // FIXME: This should use the dynamic global scope (bug #27887)
     KURL scriptURL = executionContext()->completeURL(url);
     if (!scriptURL.isValid()) {
         exceptionState.throwDOMException(SyntaxError, "Failed to create a worker: '" + url + "' is not a valid URL.");
         return KURL();
     }
 
     // We can safely expose the URL in the following exceptions, as these checks happen synchronously before redirection. JavaScript receives no new information.
     if (!executionContext()->securityOrigin()->canRequest(scriptURL)) {
         exceptionState.throwSecurityError("Failed to create a worker: script at '" + scriptURL.elidedString() + "' cannot be accessed from origin '" + executionContext()->securityOrigin()->toString() + "'.");
         return KURL();
     }
 
     if (executionContext()->contentSecurityPolicy() && !executionContext()->contentSecurityPolicy()->allowScriptFromSource(scriptURL)) {
         exceptionState.throwSecurityError("Failed to create a worker: access to the script at '" + scriptURL.elidedString() + "' is denied by the document's Content Security Policy.");
         return KURL();
     }
 
     return scriptURL;
 }
 
 } // namespace WebCore