Reimplement CatServlet as a redirect to the DownloadContent
REST API method. Enable DownloadServlet to serve content from
parent commits upon request.
It isn't possible to reference a base commit as a revision ID
in a REST URL. A new parent parameter for DownloadContent
provides access to parent commits, replacing the obsolete
suffix parameter. A positive value of N will reference the
Nth parent commit for the specified revision. If the parameter
is missing or its value is zero, the patch commit is referenced.
The suffix for the download is now computed directly by the
DownloadContent method. The suffix is "_new" for a file from
a patch set, "_old" for a file from the base commit when there's
a single parent, or "oldN" for the Nth parent commit of many.
Change-Id: Ibedf07a62ddf6661f4050da21df7a3c7a8681c0c
ec622bf71a