Extension SW: Add tests that serve web_accessible_resources from a SW.

chrome/test/data/extensions/api_test/service_worker/web_accessible_resources/fetch/sw.js

Index: chrome/test/data/extensions/api_test/service_worker/web_accessible_resources/fetch/sw.js
diff --git a/chrome/test/data/extensions/api_test/service_worker/web_accessible_resources/fetch/sw.js b/chrome/test/data/extensions/api_test/service_worker/web_accessible_resources/fetch/sw.js
new file mode 100644
index 0000000000000000000000000000000000000000..50ce64b5e67622ff83450772478a5dc53ffea205
--- /dev/null
+++ b/chrome/test/data/extensions/api_test/service_worker/web_accessible_resources/fetch/sw.js
@@ -0,0 +1,26 @@
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+self.onfetch = function(e) {
+  var url = new URL(e.request.url);
+  if (url.pathname == '/data_for_extension') {
+    e.respondWith(new Response('SW served data'));
+  }
+};
+
+self.onmessage = function(e) {
+  var request = e.data;
+  switch (request) {
+    case 'claim':
+      self.clients.claim().then(function() {
+        e.ports[0].postMessage('clients claimed');
+      }).catch(function(err) {
+        e.ports[0].postMessage('FAIL' + err);
+      });
+      break;
+    default:
+      e.ports[0].postMessage('FAIL: Incorrect request.');
+      break;
+  }
+};