old_contents: if (typeof importScripts === 'function') {
    var boot = function(e) {
      if (e.data.api === 'MS_LaunchWorker')  {
        self.removeEventListener('message', boot, false);
        self[e.data.asm_js_module_name]({ __ms_module_id__: e.data.mod_id,
                                          __ms_browser_language__: e.data.browser_language,
                                          TOTAL_MEMORY: e.data.asm_js_memory });
      }
      if (!self["performance"])
        self["performance"] = {};
      if (!self["performance"]["now"])
        self["performance"]["now"] = function() { return Date.now(); }
    };
    self.addEventListener('message', boot, false);
  }
  
new_contents: if(typeof importScripts==='function'){var b=function(e){if(e.data.api==='MS_LaunchWorker'){self.removeEventListener('message',b,false);self[e.data.asm_js_module_name]({__ms_module_id__:e.data.mod_id,__ms_browser_language__:e.data.browser_language,TOTAL_MEMORY:e.data.asm_js_memory});}};self.addEventListener('message',b,false);}
  
subject: work in progress