Implement the infrastructure of creating WorkerFetchContext in worker global scope.

third_party/WebKit/Source/core/loader/WorkerFetchContext.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 WorkerFetchContext_h
+#define WorkerFetchContext_h
+
+#include <memory>
+#include "core/CoreExport.h"
+#include "platform/loader/fetch/FetchContext.h"
+#include "platform/wtf/Forward.h"
+
+namespace blink {
+
+class WorkerClients;
+class WebURLLoader;
+class WebWorkerFetchContext;
+class WorkerGlobalScope;
+
+CORE_EXPORT void ProvideWorkerFetchContextToWorker(
+    WorkerClients*,
+    std::unique_ptr<WebWorkerFetchContext>);
+
+// The WorkerFetchContext is a FetchContext for workers (dedicated, shared and
+// service workers). This class is used only when off-main-thread-fetch is
+// enabled, and is still under development.
+// TODO(horo): Implement all methods of FetchContext. crbug.com/443374
+class WorkerFetchContext final : public FetchContext {
+ public:
+  static WorkerFetchContext* Create(WorkerGlobalScope&);
+  virtual ~WorkerFetchContext();
+
+  // FetchContext implementation:
+  // TODO(horo): Implement more methods.
+  std::unique_ptr<WebURLLoader> CreateURLLoader() override;
+  void PrepareRequest(ResourceRequest&, RedirectType) override;
+  bool IsControlledByServiceWorker() const override;
+
+ private:
+  explicit WorkerFetchContext(std::unique_ptr<WebWorkerFetchContext>);
+
+  std::unique_ptr<WebWorkerFetchContext> web_context_;
+};
+
+}  // namespace blink
+
+#endif  // WorkerFetchContext_h