Use defer out-params instead of ResourceDispatcherHostImpl::PauseRequest(...true)

content/browser/download/download_request_handle.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.
 
 #ifndef CONTENT_BROWSER_DOWNLOAD_DOWNLOAD_REQUEST_HANDLE_H_
 #define CONTENT_BROWSER_DOWNLOAD_DOWNLOAD_REQUEST_HANDLE_H_
 #pragma once
 
 #include <string>
 
 #include "base/compiler_specific.h"
+#include "base/memory/ref_counted.h"
+#include "content/browser/download/download_resource_handler.h"
 #include "content/common/content_export.h"
 
 namespace content {
 class DownloadManager;
 class WebContents;
 }
 
 // A handle used by the download system for operations on the URLRequest
 // or objects conditional on it (e.g. WebContentsImpl).
 // This class needs to be copyable, so we can pass it across threads and not
@@ skipping 16 matching lines @@
   virtual void CancelRequest() const = 0;
 
   // Describe the object.
   virtual std::string DebugString() const = 0;
 };
 
 
 class CONTENT_EXPORT DownloadRequestHandle
     : public DownloadRequestHandleInterface {
  public:
+  virtual ~DownloadRequestHandle();
+
   // Create a null DownloadRequestHandle: getters will return null, and
   // all actions are no-ops.
   // TODO(rdsmith): Ideally, actions would be forbidden rather than
   // no-ops, to confirm that no non-testing code actually uses
   // a null DownloadRequestHandle.  But for now, we need the no-op
   // behavior for unit tests.  Long-term, this should be fixed by
   // allowing mocking of ResourceDispatcherHost in unit tests.
   DownloadRequestHandle();
 
   // Note that |rdh| is required to be non-null.
-  DownloadRequestHandle(int child_id,
+  DownloadRequestHandle(DownloadResourceHandler* handler,
+                        int child_id,
                         int render_view_id,
                         int request_id);
 
   // Implement DownloadRequestHandleInterface interface.
   virtual content::WebContents* GetWebContents() const OVERRIDE;
   virtual content::DownloadManager* GetDownloadManager() const OVERRIDE;
   virtual void PauseRequest() const OVERRIDE;
   virtual void ResumeRequest() const OVERRIDE;
   virtual void CancelRequest() const OVERRIDE;
   virtual std::string DebugString() const OVERRIDE;
 
  private:
+  scoped_refptr<DownloadResourceHandler> handler_;

[Randy Smith (Not in Mondays), 2012/05/17 15:53:48]

Shouldn't this be a weak pointer?  I could easily imagine the handle outliving
the Handler.

[darin (slow to review), 2012/05/17 21:17:57]

It seems OK to extend the lifetime of the Handler.  It is thread-safe ref
counted and it gets destroyed on the IO thread.  A weak pointer would also be OK
since the handler lives as long as the URLRequest, and if the URLRequest is
gone, then there is no point in pausing / resuming / cancelling the URLRequest. 
Hmm... maybe weak is better.

+
   // The ID of the child process that started the download.
   int child_id_;
 
   // The ID of the render view that started the download.
   int render_view_id_;
 
   // The ID associated with the request used for the download.
   int request_id_;
 };
 
 #endif  // CONTENT_BROWSER_DOWNLOAD_DOWNLOAD_REQUEST_HANDLE_H_