Use window.testRunner in if-clause

third_party/WebKit/LayoutTests/fullscreen/full-screen-frameset.html

 <script src="full-screen-test.js"></script>
 <script>
 if (window.testRunner)
     testRunner.dumpChildFramesAsText();
 
 var waitingFor = 2;
 function runTest() {
     if (--waitingFor)
         return;
     var frame = document.getElementById('frame');
 
     waitForEvent(frame.contentDocument, 'webkitfullscreenchange', function() { 
             consoleWrite("FAIL - entered full screen!");
             endTest(); 
-            if (testRunner)
+            if (window.testRunner)
                 testRunner.notifyDone();     
     });
 
     runWithKeyDown(function() {
 
         setTimeout(function() { 
             consoleWrite("SUCCEED - did not enter full screen!"); 
             endTest();
-            if (testRunner)
+            if (window.testRunner)
                 testRunner.notifyDone();     
         }, 50);
 
         frame.contentDocument.documentElement.webkitRequestFullScreen();
     });
 }
 </script>
 <frameset rows="150,*">
     <frame name="header" src="resources/not-allowed.html" onload="runTest()">
     <frame id="frame" name="frame" src="resources/inner.html" allowfullscreen onload="runTest()">
 </frameset>