Replace the DownloadFileManager with direct ownership of DownloadFileImpl

content/browser/download/base_file.cc

Index: content/browser/download/base_file.cc
diff --git a/content/browser/download/base_file.cc b/content/browser/download/base_file.cc
index cad472f5adc3c337afba57b871a5d9b9098c8ba9..6cbe98e3eb0fbf0d3334a6238ecf2d16fadb27f0 100644
--- a/content/browser/download/base_file.cc
+++ b/content/browser/download/base_file.cc
@@ -220,13 +220,7 @@ BaseFile::BaseFile(const FilePath& full_path,
       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()) {
-    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.
@@ -249,6 +243,11 @@ net::Error BaseFile::Initialize(const FilePath& default_directory) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
   DCHECK(!detached_);
 
+  if (file_stream_.get()) {
+    file_stream_->SetBoundNetLogSource(bound_net_log_);
+    file_stream_->EnableErrorStatistics();
+  }
+
   if (full_path_.empty()) {
     FilePath initial_directory(default_directory);
     FilePath temp_file;