Create ServiceWorkerProviderHost before starting worker

content/browser/service_worker/service_worker_version.h

Index: content/browser/service_worker/service_worker_version.h
diff --git a/content/browser/service_worker/service_worker_version.h b/content/browser/service_worker/service_worker_version.h
index 917fe64bf6a7e3eb4836136bace13309dd57bb6c..35a4c2e7100dde4c27c00ca83c5a271ff48946db 100644
--- a/content/browser/service_worker/service_worker_version.h
+++ b/content/browser/service_worker/service_worker_version.h
@@ -303,6 +303,10 @@ class CONTENT_EXPORT ServiceWorkerVersion
     return controllee_map_;
   }
 
+  // The provider host hosting this version. Only valid while the version is
+  // running.
+  ServiceWorkerProviderHost* provider_host() { return provider_host_.get(); }
+
   base::WeakPtr<ServiceWorkerContextCore> context() const { return context_; }
 
   // Adds and removes |request_job| as a dependent job not to stop the
@@ -555,6 +559,7 @@ class CONTENT_EXPORT ServiceWorkerVersion
   // EmbeddedWorkerInstance::Listener overrides:
   void OnThreadStarted() override;
   void OnStarting() override;
+  void OnStartWorkerMessageSent() override;
   void OnStarted() override;
   void OnStopping() override;
   void OnStopped(EmbeddedWorkerStatus old_status) override;
@@ -723,6 +728,15 @@ class CONTENT_EXPORT ServiceWorkerVersion
 
   std::set<const ServiceWorkerURLRequestJob*> streaming_url_request_jobs_;
 
+  // Keeps track of the provider hosting worker's context for this version.
+  // |pending_provider_host_| is valid from StartWorkerInternal to
+  // OnStartWorkerMessageSent. On OnStartWorkerMessageSent, the ownership will
+  // be passed to ServiceWorkerContextCore.
+  // |provider_host_| is always valid as long as this version has
+  // the running context.
+  std::unique_ptr<ServiceWorkerProviderHost> pending_provider_host_;
+  base::WeakPtr<ServiceWorkerProviderHost> provider_host_;
+
   std::map<std::string, ServiceWorkerProviderHost*> controllee_map_;
   // Will be null while shutting down.
   base::WeakPtr<ServiceWorkerContextCore> context_;