Fix Javascript typo in LazyBackgroundPageApiTest

BUG=
TEST=


Review URL: http://codereview.chromium.org/8392025

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@107850 0039d316-1c4b-4281-b951-d872f2087c98

chrome/test/data/extensions/api_test/lazy_background_page/broadcast_event/background.html

 <script>
 chrome.tabs.onUpdated.addListener(function(tabId, changeInfo, tab) {
   // TODO: look for 'stegosaurus' in the page contents.
-  if (tab.url.search("stegosaurus"))
+  if (tab.url.search("stegosaurus") > -1)
     chrome.pageAction.show(tabId);
   else
     chrome.pageAction.hide(tabId);