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

content/public/browser/service_worker_context.h

Index: content/public/browser/service_worker_context.h
diff --git a/content/public/browser/service_worker_context.h b/content/public/browser/service_worker_context.h
index 90c3d93ad587025b5c88774716313c632e1a94e7..47ff30f10ac5380a178d5652470d27fa566ea3f4 100644
--- a/content/public/browser/service_worker_context.h
+++ b/content/public/browser/service_worker_context.h
@@ -52,9 +52,10 @@ class ServiceWorkerContext {
   static bool IsExcludedHeaderNameForFetchEvent(const std::string& header_name);
 
   // Equivalent to calling navigator.serviceWorker.register(script_url, {scope:
-  // pattern}) from a renderer, except that |pattern| is an absolute URL instead
-  // of relative to some current origin.  |callback| is passed true when the JS
-  // promise is fulfilled or false when the JS promise is rejected.
+  // pattern, bool: use_cache}) from a renderer, except that |pattern| is an

[nhiroki, 2017/03/24 00:33:42]

"bool: use_cache" => "useCache: use_cache" ?

[yuryu, 2017/03/28 05:08:56]

Done.

+  // absolute URL instead of relative to some current origin.  |callback| is
+  // passed true when the JS promise is fulfilled or false when the JS promise
+  // is rejected.
   //
   // The registration can fail if:
   //  * |script_url| is on a different origin from |pattern|
@@ -67,6 +68,7 @@ class ServiceWorkerContext {
   // be called on the UI thread.
   virtual void RegisterServiceWorker(const Scope& pattern,
                                      const GURL& script_url,
+                                     bool use_cache,

[falken, 2017/03/24 04:06:19]

Do we need to expose this use_cache to ServiceWorkerContext, or is it possible
to be only on ServiceWorkerContextCore? We may be able to save some callsites
passing false if it's just ContextCore that needs it.

Also, seems better if we can use ServiceWorkerRegistrationOptions here instead
of the individual paramenters.

[yuryu, 2017/03/24 04:45:55]

https://cs.chromium.org/chromium/src/content/browser/service_worker/link_head...

link_header_support.c uses ServiceWorkerContext, and it also needs control of
useCache (and WorkerType in the future). So I think we need to change it to use
ServiceWorkerRegistrationOptions too. Am I correct?

[falken, 2017/03/27 06:15:37]

Yes, you're right.

[yuryu, 2017/03/28 05:08:56]

Acknowledged.

                                      const ResultCallback& callback) = 0;
 
   // Mechanism for embedder to increment/decrement ref count of a service