[network service][SW] Rework browser-side SW on top of URL loader chaining

content/browser/service_worker/service_worker_version.cc

Index: content/browser/service_worker/service_worker_version.cc
diff --git a/content/browser/service_worker/service_worker_version.cc b/content/browser/service_worker/service_worker_version.cc
index cb79637f758036a12b2f217f3197150e7b74f4aa..1a812b201f314583a69a9a12f2f05b587b6a0457 100644
--- a/content/browser/service_worker/service_worker_version.cc
+++ b/content/browser/service_worker/service_worker_version.cc
@@ -42,6 +42,7 @@
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/content_browser_client.h"
 #include "content/public/browser/render_process_host.h"
+#include "content/public/common/browser_side_navigation_policy.h"
 #include "content/public/common/content_client.h"
 #include "content/public/common/content_switches.h"
 #include "content/public/common/result_codes.h"
@@ -903,7 +904,13 @@ void ServiceWorkerVersion::OnDetached(EmbeddedWorkerStatus old_status) {
 }
 
 void ServiceWorkerVersion::OnScriptLoaded() {
-  DCHECK(GetMainScriptHttpResponseInfo());
+  DCHECK(GetMainScriptHttpResponseInfo() ||
+         // TODO(scottmg|falken): This DCHECK is currently triggered in
+         // --network-service because subresources haven't been implemented yet.

[falken, 2017/06/06 13:20:23]

In the non-servicifiied path,  ServiceWorkerReadFromCacheJob would set the http
response info. So, if this DCHECK is now failing, it's not really that
subresources are not implemented, it's that the service worker script reading is
not implemented.

In the servicified path, I'm a bit surprised that the service worker is able to
start at all if ServiceWorkerReadFromCacheJob is not being used. I guess it's
because we are fetching the service worker from network each time.

[scottmg, 2017/06/06 16:50:09]

I see. OK, I updated the comment. I think I got confused between the fetch of
the contents of index.html and the retrieval of the service worker js itself.

I'll continue with this as-is to avoid making this CL even messier, and then we
can look at whether to reuse ServiceWorkerReadFromCacheJob or implement
something similar.

+         // This should be removed once that is complete.
+         (IsBrowserSideNavigationEnabled() &&
+          base::CommandLine::ForCurrentProcess()->HasSwitch(
+              switches::kEnableNetworkService)));
   if (IsInstalled(status()))
     UMA_HISTOGRAM_BOOLEAN("ServiceWorker.ScriptLoadSuccess", true);
 }