Implement updateViaCache flag and no-cache by default for main service worker scripts

content/browser/service_worker/service_worker_database.proto

 // Copyright 2014 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.
 
 syntax = "proto2";
 
 option optimize_for = LITE_RUNTIME;
 
 package content;
 
@@ skipping 36 matching lines @@
   // |origin_trial_tokens| is not set. In this case, we have to start the
   // Service Worker and load the main script resource in ServiceWorkerStorage
   // to check the HTTP header.
   optional ServiceWorkerOriginTrialInfo origin_trial_tokens = 11;
 
   optional ServiceWorkerNavigationPreloadState navigation_preload_state = 12;
 
   // The set of features that the worker used up until the time installation
   // completed. The values must be from blink::UseCounter::Feature enum.
   repeated uint32 used_features = 13;
+
+  optional uint32 update_via_cache = 14;

[nhiroki, 2017/06/21 14:08:35]

How about using Enum?
https://developers.google.com/protocol-buffers/docs/proto#enum

[yuryu, 2017/07/20 10:15:12]

Done.

 }
 
 message ServiceWorkerResourceRecord {
   required int64 resource_id = 1;
   required string url = 2;
   optional uint64 size_bytes = 3;
 }