Relanding this patch with the compile fix for Visual studio 2005. The compile...

Relanding this patch with the compile fix for Visual studio 2005. The compiler gets
confused between the two Delegate classes URLRequest::Delegate and the
PluginDownloadHelper::Delegate class. Renaming the latter seems to work

Fix a regression introduced in the chrome plugin installer on Windows in revision 54316
which was to remove usages of GetTempDir. However the change failed to take into account
that the file name which is used to perform the download eventually is shell executed on
windows. In this case the download was performed on a temporary file which causes ShellExecute
to put up a confirmation dialog asking the user to select the application for opening the file.

Fix is to rename the temp file path to the desired file path on success.

Fixes bug http://code.google.com/p/chromium/issues/detail?id=56746

Bug=56746
Test=Covered by plugin installer plugin test.

TBR=jam


Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=60577