[ServiceWorker] Add error handling code fetch-mixed-content-iframe.html to avoid timeouts.

BUG=426047

Review URL: https://codereview.chromium.org/672423003

git-svn-id: svn://svn.chromium.org/blink/trunk@184333 bbb929c8-8fbe-4397-9dbb-9b2b20218538

third_party/WebKit/LayoutTests/http/tests/serviceworker/resources/fetch-mixed-content-iframe.html

@@ -24,6 +24,10 @@ navigator.serviceWorker.getRegistration(SCOPE)
     })
   .then(function(worker) {
       worker.addEventListener('statechange', on_state_change);
+    })
+  .catch(function(reason) {
+      window.parent.postMessage({results: 'FAILURE: ' + reason.message},
+                                host_info['HTTP_ORIGIN']);
      });
 
 function on_state_change(event) {
@@ -42,6 +46,10 @@ function on_message(e) {
       })
     .then(function() {
       window.parent.postMessage(e.data, host_info['HTTP_ORIGIN']);
+    })
+    .catch(function(reason) {
+        window.parent.postMessage({results: 'FAILURE: ' + reason.message},
+                                  host_info['HTTP_ORIGIN']);
      });
 }
 </script>