Implement the infrastructure of creating WorkerFetchContext in worker global scope.

third_party/WebKit/public/web/modules/serviceworker/WebServiceWorkerContextClient.h

Index: third_party/WebKit/public/web/modules/serviceworker/WebServiceWorkerContextClient.h
diff --git a/third_party/WebKit/public/web/modules/serviceworker/WebServiceWorkerContextClient.h b/third_party/WebKit/public/web/modules/serviceworker/WebServiceWorkerContextClient.h
index 4b8c565edbc49ab90c28183cf91ca6a8bc4c2700..16cceca84b8e2458b83f8f46a89bd8efcee5c6c3 100644
--- a/third_party/WebKit/public/web/modules/serviceworker/WebServiceWorkerContextClient.h
+++ b/third_party/WebKit/public/web/modules/serviceworker/WebServiceWorkerContextClient.h
@@ -51,6 +51,7 @@ class WebServiceWorkerNetworkProvider;
 class WebServiceWorkerProvider;
 class WebServiceWorkerResponse;
 class WebString;
+class WebWorkerFetchContext;
 
 // This interface is implemented by the client. It is supposed to be created
 // on the main thread and then passed on to the worker thread by a newly
@@ -232,6 +233,13 @@ class WebServiceWorkerContextClient {
     return nullptr;
   }
 
+  // Creates a WebWorkerFetchContext for a service worker. Ownership of the
+  // returned object is transferred to the caller. This is called on the main
+  // thread. This is used only when off-main-thread-fetch is enabled.
+  virtual blink::WebWorkerFetchContext* CreateServiceWorkerFetchContext() {

[nhiroki, 2017/04/20 04:16:07]

How about returning std::unique_ptr<WebWorkerFetchContext>?

[horo, 2017/04/20 08:35:43]

Done.

+    return nullptr;
+  }
+
   // Ownership of the returned object is transferred to the caller.
   // This is called on the main thread.
   virtual WebServiceWorkerProvider* CreateServiceWorkerProvider() {