Fix race where sometimes CSS is not applied to toolstrips. I

chrome/test/data/extensions/samples/buildbot/buildbot.html

 <script>
 
 var botRoot = "http://build.chromium.org/buildbot/waterfall";
 
 var botUrl = botRoot + "/horizontal_one_box_per_builder";
 
 function updateStatus(status) {
   var div = document.getElementById("status");
   div.title = status;
   var open = /open/i;
@@ skipping 39 matching lines @@
   }
   setTimeout(requestStatus, 30000);
 }
 
 function statusClick() {
   window.open(botRoot);
 }
 
 requestStatus();
 </script>
-<link rel="stylesheet" type="text/css" href="extensions_toolstrip.css">
 <style>
 .open {
   color: green;
 }
 
 .closed {
   color: red;
 }
 
 #bots {
@@ skipping 16 matching lines @@
 
 </style>
 
 <div class="toolstrip-button" onclick="statusClick();">
 <span id="status" class="open">tree: open?</span>
 </div>
 
 <div id="frame-wrapper">
 <iframe scrolling='no' id='bots' src="http://build.chromium.org/buildbot/waterfall/horizontal_one_box_per_builder"></iframe>
 </div>