Added member data to classes to support download resumption.

content/browser/download/download_resource_handler.h

 // Copyright (c) 2011 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_RESOURCE_HANDLER_H_
 #define CONTENT_BROWSER_DOWNLOAD_DOWNLOAD_RESOURCE_HANDLER_H_
 #pragma once
 
 #include <string>
 
 #include "base/callback.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/timer.h"
-#include "content/browser/download/download_file.h"
 #include "content/browser/download/download_id.h"
+#include "content/browser/download/download_types.h"
 #include "content/browser/renderer_host/global_request_id.h"
 #include "content/browser/renderer_host/resource_handler.h"
+#include "net/base/net_errors.h"
 
 class DownloadFileManager;
 class ResourceDispatcherHost;
 
 namespace content {
 class DownloadBuffer;
 }
 
 namespace net {
 class URLRequest;
@@ skipping 44 matching lines @@
                                    const std::string& security_info);
   virtual void OnRequestClosed();
 
   // If the content-length header is not present (or contains something other
   // than numbers), the incoming content_length is -1 (unknown size).
   // Set the content length to 0 to indicate unknown size to DownloadManager.
   void set_content_length(const int64& content_length);
 
   void set_content_disposition(const std::string& content_disposition);
 
+  // How many bytes were read before this request was interrupted. Should be
+  // used only by |ResourceDispatcherHost::BeginDownload()|.

[Randy Smith (Not in Mondays), 2011/11/16 18:29:27]

I'd like to think about the interface to the IO and file threads as being just
about the current request, and how they're used (to pick up where we left off)
being in the UI thread/DownloadItem.  So this comment should just say something
like "Location within the remote resource at which to start the download."

[ahendrickson, 2011/11/19 20:18:03]

Done.

+  void set_start_offset(int64 bytes) { start_offset_ = bytes; }
+
   void CheckWriteProgress();
 
   std::string DebugString() const;
 
  private:
   virtual ~DownloadResourceHandler();
 
   void StartPauseTimer();
   void CallStartedCB(net::Error error);
 
   DownloadId download_id_;
   GlobalRequestID global_id_;
   int render_view_id_;
   scoped_refptr<net::IOBuffer> read_buffer_;
   std::string content_disposition_;
   int64 content_length_;
   DownloadFileManager* download_file_manager_;
   net::URLRequest* request_;
   bool save_as_;  // Request was initiated via "Save As" by the user.
   OnStartedCallback started_cb_;
   DownloadSaveInfo save_info_;
   scoped_refptr<content::DownloadBuffer> buffer_;
   ResourceDispatcherHost* rdh_;
   bool is_paused_;
   base::OneShotTimer<DownloadResourceHandler> pause_timer_;
   base::TimeTicks download_start_time_;  // used to collect stats.
   base::TimeTicks last_read_time_;        // used to collect stats.
   size_t last_buffer_size_;               // used to collect stats.
+  int64 start_offset_;
   static const int kReadBufSize = 32768;  // bytes
   static const int kThrottleTimeMs = 200;  // milliseconds
 
   DISALLOW_COPY_AND_ASSIGN(DownloadResourceHandler);
 };
 
 #endif  // CONTENT_BROWSER_DOWNLOAD_DOWNLOAD_RESOURCE_HANDLER_H_