Added member data to classes to support download resumption.

content/browser/download/download_file_impl.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_FILE_IMPL_H_
 #define CONTENT_BROWSER_DOWNLOAD_DOWNLOAD_FILE_IMPL_H_
 #pragma once
 
 #include "content/browser/download/download_file.h"
 
@@ skipping 21 matching lines @@
                                       size_t data_len) OVERRIDE;
   virtual net::Error Rename(const FilePath& full_path) OVERRIDE;
   virtual void Detach() OVERRIDE;
   virtual void Cancel() OVERRIDE;
   virtual void Finish() OVERRIDE;
   virtual void AnnotateWithSourceInformation() OVERRIDE;
   virtual FilePath FullPath() const OVERRIDE;
   virtual bool InProgress() const OVERRIDE;
   virtual int64 BytesSoFar() const OVERRIDE;
   virtual bool GetSha256Hash(std::string* hash) OVERRIDE;
+  virtual std::string GetSha256HashState() OVERRIDE;

[Randy Smith (Not in Mondays), 2011/11/23 19:25:13]

It occurs to me to wonder--if the underlying implementation hides what type of
hash is actually being used from us, should we claim it's the Sha256 state? 
Should all of these functions just be Get/SetHashState?

   virtual void CancelDownloadRequest() OVERRIDE;
   virtual int Id() const OVERRIDE;
   virtual DownloadManager* GetDownloadManager() OVERRIDE;
   virtual const DownloadId& GlobalId() const OVERRIDE;
   virtual std::string DebugString() const OVERRIDE;
 
  private:
   // The base file instance.
   BaseFile file_;
 
   // The unique identifier for this download, assigned at creation by
   // the DownloadFileManager for its internal record keeping.
   DownloadId id_;
 
   // The handle to the request information.  Used for operations outside the
   // download system, specifically canceling a download.
   scoped_ptr<DownloadRequestHandleInterface> request_handle_;
 
   // DownloadManager this download belongs to.
   scoped_refptr<DownloadManager> download_manager_;
 
   DISALLOW_COPY_AND_ASSIGN(DownloadFileImpl);
 };
 
 #endif  // CONTENT_BROWSER_DOWNLOAD_DOWNLOAD_FILE_IMPL_H_