extensions: Fix synchronization in ContentScriptApiTest.ContentScriptOtherExtensions

chrome/test/data/extensions/api_test/content_scripts/other_extensions/iframe_content.js

Index: chrome/test/data/extensions/api_test/content_scripts/other_extensions/iframe_content.js
diff --git a/chrome/test/data/extensions/api_test/content_scripts/other_extensions/iframe_content.js b/chrome/test/data/extensions/api_test/content_scripts/other_extensions/iframe_content.js
index 0e794a0318ce4a7b62fe237c4c82c8edf785f448..2f34d9a47662fdaca70235f92cae3142f498beff 100644
--- a/chrome/test/data/extensions/api_test/content_scripts/other_extensions/iframe_content.js
+++ b/chrome/test/data/extensions/api_test/content_scripts/other_extensions/iframe_content.js
@@ -2,14 +2,11 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-document.addEventListener('DOMContentLoaded', function() {
-  var id = window.setInterval(function() {
-    clearInterval(id);
-    var parent_extension_page = unescape(location.hash.replace('#', ''));
+window.addEventListener('load', function() {
+  var parent_extension_page = unescape(location.hash.replace('#', ''));
 
-    console.log('PAGE: Sending content to parent extension page - ' +
-                parent_extension_page);
-    window.parent.postMessage(document.getElementById('content').innerText,
-                              parent_extension_page);
-  }, 10);
+  console.log('PAGE: Sending content to parent extension page - ' +
+              parent_extension_page);
+  window.parent.postMessage(document.getElementById('content').innerText,
+                            parent_extension_page);
 });