Make sure the scoped_ptr is set before checking if the file is open. Fixes a ...

Fix a crash when installing plugins.
* Make sure the scoped_ptr is initialized before trying to open a file.
* Assign the result of FilePath::Append to download_file_path_.

R=ananta
BUG=8087
Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=10787

[ananta, 2009-03-03 02:05:22]

LGTM with the following issue fixed.

In PluginDownloadUrlHelper::OnResponseStarted
Please change
download_file_path_.Append(UTF8ToWide(request_url.ExtractFileName())); 

to 
download_file_path_ =
download_file_path_.Append(UTF8ToWide(request_url.ExtractFileName()));