Revert of Pipe response_time from FetchManager to CacheStorage and ServiceWorkerURLRequestJob.

content/test/data/service_worker/fetch_event_response_via_cache.js

-// Copyright 2016 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.
-
-this.onfetch = function(event) {
-    var CACHE_NAME = 'cache_name';
-    var cache = undefined;
-    var url = event.request.url;
-    event.respondWith(
-        caches.open(CACHE_NAME)
-          .then(function(c) {
-              cache = c;
-              return cache.match(url);
-            })
-          .then(function(response) {
-              if (response)
-                return response;
-              var cloned_response = undefined;
-              return fetch(url)
-                .then(function(res) {
-                    cloned_response = res.clone();
-                    return cache.put(url, res);
-                  })
-                .then(function() {
-                    return cloned_response;
-                  });
-            }));
-  };