Adds a basic offline check to InstallableManager.

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 c095f9d1314c7fe028441bb19479c2f73d4fc99e..06a4b2d033e2a8324cc507934458293f1df3b396 100644
--- a/content/public/browser/service_worker_context.h
+++ b/content/public/browser/service_worker_context.h
@@ -18,6 +18,12 @@ enum class WebNavigationHintType;
 
 namespace content {
 
+enum class ServiceWorkerStatus {

[falken, 2017/03/17 07:54:37]

I'm a bit worried we have too many types named "Status", and this is a pretty
generic name. It's hard to distinguish this from
content::ServiceWorkerStatusCode by name.

How about ServiceWorkerExistence?

[piotrs, 2017/03/21 00:00:44]

It's not just about existence but about the extent to which it can handle
offline requests, so I'm not sold on 'existence'. At least that's the current
intention and we expect to extend this check in the future. I don't know the
codebase well enough yet, but I expected that status is probably overloaded
already. Some other options: ServiceWorker{Capability/Capacity/Class/Type/Kind}.

I went for ServiceWorkerCapability, please comment if you would prefer this to
change.

[falken, 2017/03/21 01:53:24]

SGTM.

+  NO_SERVICE_WORKER,
+  SERVICE_WORKER_NO_FETCH_HANDLER,
+  SERVICE_WORKER_WITH_FETCH_HANDLER,
+};
+
 // Represents the per-StoragePartition ServiceWorker data.
 class ServiceWorkerContext {
  public:
@@ -30,8 +36,8 @@ class ServiceWorkerContext {
   using GetUsageInfoCallback = base::Callback<void(
       const std::vector<ServiceWorkerUsageInfo>& usage_info)>;
 
-  using CheckHasServiceWorkerCallback =
-      base::Callback<void(bool has_service_worker)>;
+  using CheckServiceWorkerStatusCallback =
+      base::Callback<void(ServiceWorkerStatus status)>;
 
   using CountExternalRequestsCallback =
       base::Callback<void(size_t external_request_count)>;
@@ -109,10 +115,10 @@ class ServiceWorkerContext {
   //
   // This function can be called from any thread, but the callback will always
   // be called on the UI thread.
-  virtual void CheckHasServiceWorker(
+  virtual void CheckServiceWorkerStatus(

[falken, 2017/03/17 07:54:37]

I think the original name may be clearer.

[piotrs, 2017/03/21 00:00:44]

Reverted, Done.

       const GURL& url,
       const GURL& other_url,
-      const CheckHasServiceWorkerCallback& callback) = 0;
+      const CheckServiceWorkerStatusCallback& callback) = 0;
 
   // Returns the pending external request count for the worker with the
   // specified |origin| via |callback|.