Eliminate globalFlag usage from http security layout tests.

LayoutTests/http/tests/security/dataURL/xss-DENIED-to-data-url-in-foreign-domain-window-open.html

Index: LayoutTests/http/tests/security/dataURL/xss-DENIED-to-data-url-in-foreign-domain-window-open.html
diff --git a/LayoutTests/http/tests/security/dataURL/xss-DENIED-to-data-url-in-foreign-domain-window-open.html b/LayoutTests/http/tests/security/dataURL/xss-DENIED-to-data-url-in-foreign-domain-window-open.html
index dd8e320c3f3e849c6722b5a9b1fe81cb8b799d9e..03914ce3e57b829a3cc77d1d855fef87cd9e17e7 100644
--- a/LayoutTests/http/tests/security/dataURL/xss-DENIED-to-data-url-in-foreign-domain-window-open.html
+++ b/LayoutTests/http/tests/security/dataURL/xss-DENIED-to-data-url-in-foreign-domain-window-open.html
@@ -12,27 +12,12 @@
                 testRunner.setCanOpenWindows();
             }
 
+            window.addEventListener('message', function ()
+            {
+                runTest();
+                closeWindowAndNotifyDone(openedWindow);
+            });
             openedWindow = window.open("http://localhost:8000/security/dataURL/resources/foreign-domain-data-url-accessee-opened-frame.html");
-
-            if (window.testRunner) {
-                setTimeout(pollForTest, 1);
-            } else {
-                log("To run the test, click the button below when the opened window finishes loading.");
-                var button = document.createElement("button");
-                button.appendChild(document.createTextNode("Run Test"));
-                button.onclick = runTest;
-                document.body.appendChild(button);
-            }
-        }
-
-        pollForTest = function()
-        {
-            if (!testRunner.globalFlag) {
-                setTimeout(pollForTest, 1);
-                return;
-            }
-            runTest();
-            closeWindowAndNotifyDone(openedWindow);
         }
 
         runTest = function()