Update web-platform-tests to revision c26470dac73f2df9d4822a0d3482f7eb1ebf57d9

tests/wpt/web-platform-tests/service-workers/service-worker/fetch-event.https.html

@@ -26,10 +26,6 @@ async_test(function(t) {
             header_names.hasOwnProperty('accept'),
             'request includes "Accept" header as inserted by Fetch'
           );
-          assert_true(
-            header_names.hasOwnProperty('upgrade-insecure-requests'),
-            'request specifies "Upgrade-Insecure Requests header as inserted by Fetch'
-          );
 
           return service_worker_unregister_and_done(t, scope);
         })

tests/wpt/web-platform-tests/service-workers/service-worker/resources/fetch-request-no-freshness-headers-iframe.html

@@ -1 +1 @@
-<script src="empty.js"></script>
+<script src="./fetch-request-no-freshness-headers-script.py"></script>

tests/wpt/web-platform-tests/service-workers/service-worker/resources/fetch-request-no-freshness-headers-script.py

@@ -0,0 +1,6 @@
+def main(request, response):
+    headers = []
+    # Sets an ETag header to check the cache revalidation behavior.
+    headers.append(("ETag", "abc123"))
+    headers.append(("Content-Type", "text/javascript"))
+    return headers, "/* empty script */"