Browser Plugin: Fixed browser process crash on embedder reload.

content/test/data/browser_plugin_embedder.html

 <script type="text/javascript">
 function SetSrc(src) {
   var plugin = document.getElementById('plugin');
   plugin.src = src;
 }
 function SetSize(w, h) {
   var plugin = document.getElementById('plugin');
   plugin.width = w;
   plugin.height = h;
 }
 function Back() {
   var plugin = document.getElementById('plugin');
   plugin.back();
 }
 function Forward() {
   var plugin = document.getElementById('plugin');
   plugin.forward();
 }
 function Go(relativeIndex) {
   var plugin = document.getElementById('plugin');
   plugin.go(relativeIndex);
 }
+function MarkAsReady() {
+  window.document.title = 'ready';
+}
+
+window.document.title = 'embedder';
 </script>
 
 <object id="plugin"
     tabindex="0"
     type="application/new-browser-plugin"
     width="640"
     height="480"
     border="0px"></object>