set content length limit if half open range request fails

content/browser/download/download_file_impl.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_FILE_IMPL_H_
 #define CONTENT_BROWSER_DOWNLOAD_DOWNLOAD_FILE_IMPL_H_
 
 #include "content/browser/download/download_file.h"
 
 #include <stddef.h>
@@ skipping 51 matching lines @@
 
   void RenameAndUniquify(const base::FilePath& full_path,
                          const RenameCompletionCallback& callback) override;
   void RenameAndAnnotate(const base::FilePath& full_path,
                          const std::string& client_guid,
                          const GURL& source_url,
                          const GURL& referrer_url,
                          const RenameCompletionCallback& callback) override;
   void Detach() override;
   void Cancel() override;
+  void SetContentLengthLimit(int64_t limit) override;
   const base::FilePath& FullPath() const override;
   bool InProgress() const override;
   void WasPaused() override;
 
  protected:
   // For test class overrides.
   // Write data from the offset to the file.
   // On OS level, it will seek to the |offset| and write from there.
   virtual DownloadInterruptReason WriteDataToFile(int64_t offset,
                                                   const char* data,
@@ skipping 162 matching lines @@
   // The default directory for creating the download file.
   base::FilePath default_download_directory_;
 
   // Map of the offset and the source stream that represents the slice
   // starting from offset.
   SourceStreams source_streams_;
 
   // Used to trigger progress updates.
   std::unique_ptr<base::RepeatingTimer> update_timer_;
 
+  // Maximum length of the file, -1 if the limit is unknown.

[xingliu, 2017/03/31 23:38:21]

nit%: It's a bit confusing that people might think this is a copy of the
Content-Length header.

[qinmin, 2017/04/01 05:20:02]

it is different, the limit is the upper bound, the actual file size could be
smaller than this. 
changed the variable name to potential_file_length_

[xingliu, 2017/04/03 16:51:56]

Thanks.

+  int64_t content_length_limit_;
+
   // Statistics
   size_t bytes_seen_;
   base::TimeDelta disk_writes_time_;
   base::TimeTicks download_start_;
   RateEstimator rate_estimator_;
   int num_active_streams_;
   bool record_stream_bandwidth_;
   base::TimeTicks last_update_time_;
   size_t bytes_seen_with_parallel_streams_;
   size_t bytes_seen_without_parallel_streams_;
   base::TimeDelta download_time_with_parallel_streams_;
   base::TimeDelta download_time_without_parallel_streams_;
 
   std::vector<DownloadItem::ReceivedSlice> received_slices_;
 
   base::WeakPtr<DownloadDestinationObserver> observer_;
   base::WeakPtrFactory<DownloadFileImpl> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(DownloadFileImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_DOWNLOAD_DOWNLOAD_FILE_IMPL_H_