Implement THROTTLED priority semantics.

content/browser/loader/resource_handler.h

 // Copyright (c) 2012 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.
 
 // This is the browser side of the resource dispatcher, it receives requests
 // from the RenderProcessHosts, and dispatches them to URLRequests. It then
 // fowards the messages from the URLRequests back to the correct process for
 // handling.
 //
 // See http://dev.chromium.org/developers/design-documents/multi-process-resource-loading
 
 #ifndef CONTENT_BROWSER_LOADER_RESOURCE_HANDLER_H_
 #define CONTENT_BROWSER_LOADER_RESOURCE_HANDLER_H_
 
 #include <string>
 
 #include "base/memory/ref_counted.h"
 #include "base/sequenced_task_runner_helpers.h"
 #include "base/threading/non_thread_safe.h"
 #include "content/common/content_export.h"
+#include "net/base/net_errors.h"
 
 class GURL;
 
 namespace net {
 class IOBuffer;
 class URLRequest;
 class URLRequestStatus;
 struct RedirectInfo;
 }  // namespace net
 
@@ skipping 56 matching lines @@
   // Call controller()->Resume() to continue reading response data.  A zero
   // |bytes_read| signals that no further data is available.
   virtual bool OnReadCompleted(int bytes_read, bool* defer) = 0;
 
   // The response is complete.  The final response status is given.  Set
   // |*defer| to true to defer destruction to a later time.  Otherwise, the
   // request will be destroyed upon return.
   virtual void OnResponseCompleted(const net::URLRequestStatus& status,
                                    bool* defer) = 0;
 
+  // The request has been cancelled.  Set |*defer| to true to defer cancellation
+  // to a later time.  Otherwise, the request will be destroyed on return.
+  virtual void OnCancel(net::Error net_error, bool* defer);

[mmenke, 2016/11/07 15:59:25]

I don't think this is supposed to be part of this CL?

+
   // This notification is synthesized by the RedirectToFileResourceHandler
   // to indicate progress of 'download_to_file' requests. OnReadCompleted
   // calls are consumed by the RedirectToFileResourceHandler and replaced
   // with OnDataDownloaded calls.
   virtual void OnDataDownloaded(int bytes_downloaded) = 0;
 
  protected:
   ResourceHandler(net::URLRequest* request);
 
   ResourceController* controller() const { return controller_; }
   net::URLRequest* request() const { return request_; }
 
   // Convenience functions.
   ResourceRequestInfoImpl* GetRequestInfo() const;
   int GetRequestID() const;
   ResourceMessageFilter* GetFilter() const;
 
  private:
   ResourceController* controller_;
   net::URLRequest* request_;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_LOADER_RESOURCE_HANDLER_H_