Replace the DownloadFileManager with direct ownership

content/public/browser/download_destination_controller.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_DESTINATION_CONTROLLER_H_
+#define CONTENT_BROWSER_DOWNLOAD_DOWNLOAD_DESTINATION_CONTROLLER_H_
+
+#include <string>
+
+#include "content/public/browser/download_interrupt_reasons.h"
+
+namespace content {
+
+// Class that receives asynchronous events from a DownloadDestination
+// about downloading progress and completion.  These describe
+// the process of writing the data to the final location (e.g. |bytes_so_far| is
+// bytes_written, and |reason| is errors occuring on writing data).

[benjhayden, 2012/07/25 15:19:16]

Then perhaps rename |bytes_so_far| to |bytes_written|?

[Randy Smith (Not in Mondays), 2012/07/30 01:07:23]

Hmmm.  What I was trying to express with this comment was the point at which the
byte flow was being measured/should be reported from was when the bytes had
landed in their final location, not when they had been consumed from the
incoming stream.  I'm not sure "bytes_written" does that any better than
"bytes_so_far" as the (abstract) download destination may not write the bytes,
it may display them, or make origami with them, or something else.  

I'll try to rewrite this comment to be clearer about what I'm trying to get at. 
If you find "bytes_so_far" confusing in itself, let me know.

+//
+// All methods must be invoked on the UI thread.
+//
+// Note that this interface does not deal with cross-thread lifetime
+// issues.
+class DownloadDestinationController {
+ public:
+  virtual void DestinationUpdate(int64 bytes_so_far,
+                                 int64 bytes_per_sec,
+                                 const std::string& hash_state) = 0;
+
+  virtual void DestinationError(DownloadInterruptReason reason) = 0;
+
+  virtual void DestinationCompleted(const std::string& final_hash) = 0;
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_DOWNLOAD_DOWNLOAD_FILE_CONTROLLER_H_