Implement the infrastructure of creating WorkerFetchContext in worker global scope.

third_party/WebKit/public/platform/WebWorkerFetchContext.h

+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef WebWorkerFetchContext_h
+#define WebWorkerFetchContext_h
+
+namespace base {
+class SingleThreadTaskRunner;
+}  // namespace base
+
+namespace blink {
+
+class WebURLLoader;
+class WebURLRequest;
+
+// WebWorkerFetchContext is a per-worker object created on the main thread,
+// passed to a worker (dedicated, shared and service worker) and initialized on
+// the worker thread by InitializeOnWorkerThread(). It contains information
+// about the resource fetching context (ex: service worker provider id), and is
+// used to create a new WebURLLoader instance in the worker thread.
+class WebWorkerFetchContext {
+ public:
+  virtual ~WebWorkerFetchContext() {}
+
+  virtual void InitializeOnWorkerThread(base::SingleThreadTaskRunner*) = 0;
+
+  // Returns a new WebURLLoader instance which is associated with the worker
+  // thread.
+  virtual std::unique_ptr<WebURLLoader> CreateURLLoader() = 0;
+
+  // Called when a request is about to be sent out to modify the request to
+  // handle the request correctly in the loading stack later. (Example: service
+  // worker)
+  virtual void WillSendRequest(WebURLRequest&) = 0;
+
+  // Whether the fetch context is controlled by a service worker.
+  virtual bool IsControlledByServiceWorker() const = 0;
+};
+
+}  // namespace blink
+
+#endif  // WebWorkerFetchContext_h