Revert of Revert of ServiceWorker: throw when close() or terminate() called

LayoutTests/http/tests/serviceworker/resources/fetch-worker.js

Index: LayoutTests/http/tests/serviceworker/resources/fetch-worker.js
diff --git a/LayoutTests/http/tests/serviceworker/resources/fetch-worker.js b/LayoutTests/http/tests/serviceworker/resources/fetch-worker.js
index 7f5d401c3f0a3e618eefac237f462b0fb9ee5b2c..b086a961b7b1a16add8165aecd62e0ef1579296a 100644
--- a/LayoutTests/http/tests/serviceworker/resources/fetch-worker.js
+++ b/LayoutTests/http/tests/serviceworker/resources/fetch-worker.js
@@ -15,12 +15,19 @@
 ];
 
 function doNextFetchTest(port) {
+
+    function runInfiniteFetchLoop() {
+      fetch('dummy.html')
+        .then(function() { runInfiniteFetchLoop(); });
+    }
+
     if (testTargets.length == 0) {
-        port.postMessage('quit');
-        // Destroying the execution context while fetch is happening should not cause a crash.
-        fetch('dummy.html').then(function() {}).catch(function() {});
-        self.close();
-        return;
+      // Destroying the execution context while fetch is happening
+      // should not cause a crash.
+      runInfiniteFetchLoop();
+
+      port.postMessage('quit');
+      return;
     }
     var target = testTargets.shift();
     fetch(target)