Replace the DownloadFileManager with direct ownership of DownloadFileImpl

content/browser/download/base_file.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/base_file.h"
 
 #include "base/bind.h"
 #include "base/file_util.h"
 #include "base/format_macros.h"
 #include "base/logging.h"
@@ skipping 191 matching lines @@
 
 // This will initialize the entire array to zero.
 const unsigned char BaseFile::kEmptySha256Hash[] = { 0 };
 
 BaseFile::BaseFile(const FilePath& full_path,
                    const GURL& source_url,
                    const GURL& referrer_url,
                    int64 received_bytes,
                    bool calculate_hash,
                    const std::string& hash_state,
                    const linked_ptr<net::FileStream>& file_stream,

[asanka, 2012/10/10 16:04:40]

linked_ptr<> isn't thread safe. Can a note be added about why the copy (while
initializing file_stream_) is safe?

                    const net::BoundNetLog& bound_net_log)
     : full_path_(full_path),
       source_url_(source_url),
       referrer_url_(referrer_url),
       file_stream_(file_stream),
       bytes_so_far_(received_bytes),
       start_tick_(base::TimeTicks::Now()),
       calculate_hash_(calculate_hash),
       detached_(false),
       bound_net_log_(bound_net_log) {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
   memcpy(sha256_hash_, kEmptySha256Hash, kSha256HashLen);
   if (file_stream_.get()) {

[asanka, 2012/10/10 16:04:40]

Suggestion: If the constructor can be called from any thread, shall we move this
use of file_stream_ to Initialize() or Open()? Open() already calls
SetBoundNetLogSource().

[Randy Smith (Not in Mondays), 2012/10/16 18:30:29]

Done.

     file_stream_->SetBoundNetLogSource(bound_net_log_);
     file_stream_->EnableErrorStatistics();
   }
 
   if (calculate_hash_) {
     secure_hash_.reset(crypto::SecureHash::Create(crypto::SecureHash::SHA256));
     if ((bytes_so_far_ > 0) &&  // Not starting at the beginning.
         (hash_state != "") &&  // Reasonably sure we have a hash state.
         (!IsEmptyHash(hash_state))) {
       SetHashState(hash_state);
@@ skipping 320 matching lines @@
 int64 BaseFile::CurrentSpeedAtTime(base::TimeTicks current_time) const {
   base::TimeDelta diff = current_time - start_tick_;
   int64 diff_ms = diff.InMilliseconds();
   return diff_ms == 0 ? 0 : bytes_so_far() * 1000 / diff_ms;
 }
 
 int64 BaseFile::CurrentSpeed() const {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
   return CurrentSpeedAtTime(base::TimeTicks::Now());
 }