Initialize the download file with correct bytes_so_far value

content/browser/download/download_file_impl.cc

 // 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.
 
 #include "content/browser/download/download_file_impl.h"
 
 #include <string>
 #include <utility>
 
 #include "base/bind.h"
@@ skipping 78 matching lines @@
 
 DownloadFileImpl::~DownloadFileImpl() {
   DCHECK_CURRENTLY_ON(BrowserThread::FILE);
   net_log_.EndEvent(net::NetLogEventType::DOWNLOAD_FILE_ACTIVE);
 }
 
 void DownloadFileImpl::Initialize(const InitializeCallback& callback) {
   DCHECK_CURRENTLY_ON(BrowserThread::FILE);
 
   update_timer_.reset(new base::RepeatingTimer());
+  int64_t bytes_so_far = 0;
+  if (is_sparse_file_) {
+    for (const auto& received_slice : received_slices_) {
+      bytes_so_far += received_slice.received_bytes;
+    }
+  } else {
+    bytes_so_far = save_info_->offset;
+  }
   DownloadInterruptReason result =
       file_.Initialize(save_info_->file_path, default_download_directory_,
-                       std::move(save_info_->file), save_info_->offset,
+                       std::move(save_info_->file), bytes_so_far,
                        save_info_->hash_of_partial_file,
                        std::move(save_info_->hash_state), is_sparse_file_);
   if (result != DOWNLOAD_INTERRUPT_REASON_NONE) {
     BrowserThread::PostTask(
         BrowserThread::UI, FROM_HERE, base::Bind(callback, result));
     return;
   }
 
   download_start_ = base::TimeTicks::Now();
 
@@ skipping 291 matching lines @@
   ByteStreamReader* stream_reader = source_stream->stream_reader();
   if (stream_reader) {
     stream_reader->RegisterCallback(base::Bind(&DownloadFileImpl::StreamActive,
                                                weak_factory_.GetWeakPtr(),
                                                source_stream));
     StreamActive(source_stream);
   }
 }
 
 int64_t DownloadFileImpl::TotalBytesReceived() const {
-  // TODO(xingliu): Use slice info to figure out total bytes received.
   return file_.bytes_so_far();
 }
 
 void DownloadFileImpl::SendUpdate() {
   // TODO(qinmin): For each active stream, add the slice it has written so
   // far along with received_slices_.
   BrowserThread::PostTask(
       BrowserThread::UI, FROM_HERE,
       base::Bind(&DownloadDestinationObserver::DestinationUpdate, observer_,
                  TotalBytesReceived(), rate_estimator_.GetCountPerSecond(),
@@ skipping 14 matching lines @@
     const base::FilePath& new_path,
     const RenameCompletionCallback& completion_callback)
     : option(option),
       new_path(new_path),
       retries_left(kMaxRenameRetries),
       completion_callback(completion_callback) {}
 
 DownloadFileImpl::RenameParameters::~RenameParameters() {}
 
 }  // namespace content