Several changes to the benchmark extension:...

chrome/test/data/extensions/samples/benchmark/script.js

 // The port for communicating back to the extension.
 var benchmarkExtensionPort = chrome.extension.connect();
 
 // The url is what this page is known to the benchmark as.
 // The benchmark uses this id to differentiate the benchmark's
 // results from random pages being browsed.
 
 // TODO(mbelshe): If the page redirects, the location changed and the
 // benchmark stalls.
 var benchmarkExtensionUrl = window.location.toString();
 
 function sendTimesToExtension() {
-  var times = window.chromium.GetLoadTimes();
+  var times = window.chrome.loadTimes();
+
   if (times.finishLoadTime != 0) {
     benchmarkExtensionPort.postMessage({message: "load", url: benchmarkExtensionUrl, values: times});
   } else {
     window.setTimeout(sendTimesToExtension, 100);
   }
 }
 
 function loadComplete() {
   // Only trigger for top-level frames (e.g. the one we benchmarked)
   if (window.parent == window) {
     sendTimesToExtension();
   }
 }
 
 window.addEventListener("load", loadComplete);