Fetcher: Disable memory caching when Service Worker handles a request

LayoutTests/http/tests/serviceworker/chromium/resources/memory-cache-worker.js

Index: LayoutTests/http/tests/serviceworker/chromium/resources/memory-cache-worker.js
diff --git a/LayoutTests/http/tests/serviceworker/chromium/resources/memory-cache-worker.js b/LayoutTests/http/tests/serviceworker/chromium/resources/memory-cache-worker.js
new file mode 100644
index 0000000000000000000000000000000000000000..ebac6d4734ec3356a38491b72ede96c478b666c6
--- /dev/null
+++ b/LayoutTests/http/tests/serviceworker/chromium/resources/memory-cache-worker.js
@@ -0,0 +1,23 @@
+var port;
+
+var promise = new Promise(function(resolve, reject) {
+    self.onmessage = function(e) {
+      var message = e.data;
+      if ('port' in message) {
+        port = message.port;
+      } else if ('ping' in message) {
+        resolve();
+      } else {
+        reject();
+      }
+    }
+  });
+
+onfetch = function(event) {
+  if (event.request.url.indexOf('memory-cache.json') != -1) {
+    event.respondWith(promise.then(function() {
+        return new Response("callback({ src : 'service worker' })");
+      }));
+    port.postMessage('ack');
+  }
+}