ServiceWorker: Fix the argument of ctor of Response

The first argument to Response constructor should be the body while
currently passing the header. This patch fixed it and updated the
pageset.

BUG=614985

Review-Url: https://codereview.chromium.org/2032893003
Cr-Commit-Position: refs/heads/master@{#397891}

tools/perf/page_sets/data/service_worker_micro_benchmark.json

 {
-    "description": "Describes the Web Page Replay archives for a user story set. Don't edit by hand! Use record_wpr for updating.", 
+    "description": "Describes the Web Page Replay archives for a story set. Don't edit by hand! Use record_wpr for updating.", 
     "archives": {
-        "service_worker_micro_benchmark_002.wpr": [
+        "service_worker_micro_benchmark_004.wpr": [
             "http://localhost:8091/index.html"
         ]
     }

tools/perf/page_sets/data/service_worker_micro_benchmark_004.wpr.sha1

+574093d63c8bcdabd89b90f7b1fd6a82e5a757ed
\ No newline at end of file

tools/perf/page_sets/service_worker_micro_benchmark.py

@@ -24,8 +24,8 @@ class ServiceWorkerMicroBenchmarkPageSet(story.StorySet):
 
     # pylint: disable=line-too-long
     # The latest code of localhost:8091 is from:
-    # https://github.com/horo-t/Service-Worker-Performance/tree/fix-flakyness
-    # (rev: 0cc35c2398526665399ca99fe53147ff81101408)
+    # https://github.com/amiq11/Service-Worker-Performance/tree/fix-flakyness
+    # (rev: e6b3f604674209a30e4cf416a18cb8be3b991abd)
     # TODO(falken): House the code in GoogleChrome's GitHub repository.
     # pylint: enable=C0301
     # Why: to measure performance of many concurrent fetches