Cancel client auth requests when not promptable.

content/test/data/workers/worker_common.js

 // Track the number of clients for this worker - tests can use this to ensure
 // that shared workers are actually shared, not distinct.
 var num_clients = 0;
 
 if (!self.postMessage) {
   // This is a shared worker - mimic dedicated worker APIs
   onconnect = function(event) {
     num_clients++;
     event.ports[0].onmessage = function(e) {
       self.postMessage = function(msg) {
@@ skipping 11 matching lines @@
   else if (evt.data == "auth")
     importScripts("/auth-basic");
   else if (evt.data == "close")
     close();
   else if (/eval.+/.test(evt.data)) {
     try {
       postMessage(eval(evt.data.substr(5)));
     } catch (ex) {
       postMessage(ex);
     }
+  } else if (/tls-client-auth.+/.test(evt.data)) {
+    try {
+      importScripts(evt.data.substr(16));
+    } catch (ex) {
+    }
+    postMessage("done");
   }
 }