Always report access control failure if accessing unsupported URL.

LayoutTests/http/tests/xmlhttprequest/resources/cross-origin-unsupported-url.js

+if (self.importScripts)
+    importScripts("/js-test-resources/js-test.js");
+
+self.jsTestIsAsync = true;
+
+description("Test cross-origin XHRs to CORS-unsupported protocol schemes in the URL.");
+
+var xhr;
+var errorEvent;
+function issueRequest(url, contentType)
+{
+    xhr = new XMLHttpRequest();
+    xhr.open('POST', url);
+    xhr.onerror = function (a) {
+        errorEvent = a;
+        shouldBeEqualToString("errorEvent.type", "error");
+        setTimeout(runTest, 0);
+    };
+    // Assumed a Content-Type that turns it into a non-simple CORS request.
+    if (contentType)
+        xhr.setRequestHeader('Content-Type', contentType);
+
+    if (self.importScripts) {
+        // Initiating the load on the main thread is not performed synchronously,
+        // so send() will not have an exception code set by the time it
+        // completes in the Worker case. Hence, no exception will be
+        // thrown by the operation.
+        shouldNotThrow('xhr.send()');
+    } else {
+        // The implementation of send() throws an exception if an
+        // exception code has been set, regardless of the sync flag.
+        // The spec restricts this to sync only, but as error progress
+        // events provide no actionable information, it is more helpful
+        // to the user to not follow spec.
+        //
+        // As the initiation of the request happens synchronously in send(),
+        // and it is determined that it is to an unsupported CORS URL, an
+        // exception is expected to be thrown.
+        shouldThrow('xhr.send()');
+    }
+}
+
+var withContentType = true;
+var tests = [ 'http://localhost:1291a/',
+              'ftp://127.0.0.1',
+              'localhost:8080/',
+              'tel:1234' ];
+
+function runTest()
+{
+    if (!tests.length && withContentType) {
+        finishJSTest();
+        return;
+    }
+    withContentType = !withContentType;
+    if (!withContentType)
+        issueRequest(tests[0]);
+    else
+        issueRequest(tests.shift(), 'application/json');
+}
+runTest();