Import w3c tests for the service workers

third_party/WebKit/LayoutTests/imported/wpt/service-workers/service-worker/resources/dummy-worker-interceptor.js

+importScripts('get-host-info.sub.js');
+
+var worker_text = 'postMessage("worker loading intercepted by service worker"); ';
+
+self.onfetch = function(event) {
+  if (event.request.url.indexOf('synthesized') != -1) {
+    event.respondWith(new Response(worker_text));
+  } else if (event.request.url.indexOf('same-origin') != -1) {
+    event.respondWith(fetch('dummy-worker-script.py'));
+  } else if (event.request.url.indexOf('cors') != -1) {
+    var path = (new URL('dummy-worker-script.py', self.location)).pathname;
+    var url = get_host_info()['HTTPS_REMOTE_ORIGIN'] + path;
+    var mode = "no-cors";
+    if (event.request.url.indexOf('no-cors') == -1) {
+      url += '?ACAOrigin=*';
+      mode = "cors";
+    }
+    event.respondWith(fetch(url, { mode: mode }));
+  }
+};
+