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

content/browser/service_worker/service_worker_database.proto

Index: content/browser/service_worker/service_worker_database.proto
diff --git a/content/browser/service_worker/service_worker_database.proto b/content/browser/service_worker/service_worker_database.proto
index 892001d00c0b94865b7c3f068984b62b5365fbe2..84737e9b463c06be36b8da2aaca0b4cfe4ee70ad 100644
--- a/content/browser/service_worker/service_worker_database.proto
+++ b/content/browser/service_worker/service_worker_database.proto
@@ -54,6 +54,8 @@ message ServiceWorkerRegistrationData {
   // 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 {