Update references to the extension messaging APIs to point to the "runtime"

chrome/test/data/extensions/api_test/executescript/in_frame/script.js

 function getStyle(elem, name) {
   if (document.defaultView && document.defaultView.getComputedStyle) {
     name = name.toLowerCase();
 
     try {
       var s = document.defaultView.getComputedStyle(elem, '');
       return s && s.getPropertyValue(name);
     } catch (ex) {
       return null;
     }
   } else {
     return null;
   }
 }
 
 var bElement = document.getElementById('test2');
 var display = getStyle(bElement, 'display').toLowerCase();
-var extensionPort = chrome.extension.connect();
+var extensionPort = chrome.runtime.connect();
 extensionPort.postMessage({message: display});