Headless utility classes for making deterministic protocol handlers

headless/public/util/managed_dispatch_url_request_job.h

Index: headless/public/util/managed_dispatch_url_request_job.h
diff --git a/headless/public/util/managed_dispatch_url_request_job.h b/headless/public/util/managed_dispatch_url_request_job.h
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+// Copyright 2016 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 HEADLESS_PUBLIC_UTIL_MANAGED_DISPATCH_URL_REQUEST_JOB_H_
+#define HEADLESS_PUBLIC_UTIL_MANAGED_DISPATCH_URL_REQUEST_JOB_H_
+
+#include "base/macros.h"
+#include "net/base/net_errors.h"
+#include "net/url_request/url_request.h"
+#include "net/url_request/url_request_job.h"
+
+namespace headless {
+class URLRequestDispatcher;
+
+// A ManagedDispatchURLRequestJob exists to allow a URLRequestDispatcher control
+// the order in which a set of fetches complete. Typically this is done to make
+// fetching deterministic. NOTE URLRequestDispatcher sub classes use
+// OnHeadersComplete and OnStartError to drive the URLRequestJob.
+class ManagedDispatchURLRequestJob : public net::URLRequestJob {
+ public:
+  ManagedDispatchURLRequestJob(net::URLRequest* request,
+                               net::NetworkDelegate* network_delegate,
+                               URLRequestDispatcher* url_request_dispatcher);
+
+  ~ManagedDispatchURLRequestJob() override;
+
+  // Tells the net::URLRequestJob that the data has been fetched and is ready to
+  // be consumed.
+  virtual void OnHeadersComplete();
+
+  // Tells the net::URLRequestJob that the fetch failed.
+  virtual void OnStartError(net::Error error);
+
+ protected:
+  // net::URLRequestJob implementation:
+  void Kill() override;
+
+  // Tell the dispatcher the request failed.
+  virtual void DispatchStartError(net::Error error);
+
+  // Tell the dispatcher the data is ready for the net stack to consume.
+  virtual void DispatchHeadersComplete();
+
+  URLRequestDispatcher* url_request_dispatcher_;  // Not owned.
+
+ private:
+  // Derived classes should not use NotifyHeadersComplete or NotifyStartError
+  // directly. Instead they should use DispatchHeadersComplete or
+  // DispatchStartError.
+  using URLRequestJob::NotifyHeadersComplete;
+  using URLRequestJob::NotifyStartError;
+
+  DISALLOW_COPY_AND_ASSIGN(ManagedDispatchURLRequestJob);
+};
+
+}  // namespace headless
+
+#endif  // HEADLESS_PUBLIC_UTIL_MANAGED_DISPATCH_URL_REQUEST_JOB_H_