Test file errors in downloads.

content/browser/download/download_file_manager.h

Index: content/browser/download/download_file_manager.h
diff --git a/content/browser/download/download_file_manager.h b/content/browser/download/download_file_manager.h
index b5f1654c4a74bf5323f64988d9fc932bb992fe76..779dafa79c6368ce49b0eec33ce9e19eb2cc2f33 100644
--- a/content/browser/download/download_file_manager.h
+++ b/content/browser/download/download_file_manager.h
@@ -144,6 +144,14 @@ class CONTENT_EXPORT DownloadFileManager
     return downloads_.size();
   }
 
+  void SetFileFactoryForTesting(scoped_ptr<DownloadFileFactory> file_factory) {
+    download_file_factory_.swap(file_factory);

[cbentzel, 2012/03/01 15:44:20]

What are you trying to do with the swap here (as opposed to reset?)

[ahendrickson, 2012/03/01 20:19:31]

This effectively does the same thing as

download_file_factory_.reset(file_factory.release());

swap() method:  file_factory will destroy the old pointer when it goes out of
scope.

reset() method:  the old pointer is destroyed when by reset(), and file_factory
becomes NULL.

I can use the reset() method if you't prefer.

[cbentzel, 2012/03/01 22:32:00]

OK, normally when I see swap I expect there to be a transfer of ownership. In
this case, the ownership would transfer but then file_factory will go out of
scope in this block. This is fine. Maybe you could use Pass here?

[ahendrickson, 2012/03/02 21:58:47]

Went the reset() way.

+  }
+
+  DownloadFileFactory* GetFileFactoryForTesting() const {
+    return download_file_factory_.get();  // Explicitly NOT a scoped_ptr.
+  }
+
  private:
   friend class base::RefCountedThreadSafe<DownloadFileManager>;
   friend class DownloadFileManagerTest;