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

content/browser/service_worker/service_worker_context_request_handler.cc

Index: content/browser/service_worker/service_worker_context_request_handler.cc
diff --git a/content/browser/service_worker/service_worker_context_request_handler.cc b/content/browser/service_worker/service_worker_context_request_handler.cc
index 364e41f751beaf928cc93d5cc3605488c981ab52..611dee845e3acfa6b98f89b3adc912aaf96b18b0 100644
--- a/content/browser/service_worker/service_worker_context_request_handler.cc
+++ b/content/browser/service_worker/service_worker_context_request_handler.cc
@@ -209,7 +209,13 @@ net::URLRequestJob* ServiceWorkerContextRequestHandler::MaybeCreateJobImpl(
   int extra_load_flags = 0;
   base::TimeDelta time_since_last_check =
       base::Time::Now() - registration->last_update_check();
-  if (time_since_last_check > kServiceWorkerScriptMaxCacheAge ||
+  bool no_update_via_cache =

[nhiroki, 2017/06/21 15:04:59]

|no_update_via_cache| sounds a bit confusing. How about |should_bypass_cache|?

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

Done.

+      (is_main_script && registration->update_via_cache() !=
+                             blink::WebServiceWorkerUpdateViaCache::kAll) ||
+      (!is_main_script && registration->update_via_cache() ==

[nhiroki, 2017/06/21 15:04:59]

|!is_main_script| would be unnecessary.

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

I intended to reflect the spec, where algorithms for main scripts and imported
scripts are separately written.
https://w3c.github.io/ServiceWorker/#importscripts
But I agree, it is not necessary.

+                              blink::WebServiceWorkerUpdateViaCache::kNone);
+  if (no_update_via_cache ||
+      time_since_last_check > kServiceWorkerScriptMaxCacheAge ||
       version_->force_bypass_cache_for_scripts()) {
     extra_load_flags = net::LOAD_BYPASS_CACHE;
   }