Add support to put a patchset into a subdirectory.

Add support to put a patchset into a subdirectory.

Add better code to handle diff header, especially add more patch verification
code.

Add a lot of tests.

Add mangling of \ to /.

R=dpranke@chromium.org
BUG=78561
TEST=

Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=81017

[Dirk Pranke, 2011-04-07 02:10:53]

Looks more-or-less fine. I assume that there's a separate patch that actually
makes use of this function? It's a little hard to tell what it'll be used for
with no context.

[M-A Ruel, 2011-04-07 14:06:47]

I had forgot to put the bug number.
http://code.google.com/p/chromium/issues/detail?id=78561 will give more context.

[M-A Ruel, 2011-04-07 14:07:59]

But the patch is probably wrong as-is. I'll ping you once I've done with the
commit-queue part, I'm writing unit tests atm.

[M-A Ruel, 2011-04-08 16:58:59]

Sent the commit queue part for review at http://codereview.chromium.org/6813044/
and I indeed needed to rework the code.

I added a lot of safeguard to make the patch code much more resilient. I added a
significant number of tests too.

[Dirk Pranke, 2011-04-08 21:49:27]

LGTM. This is something of a rubber-stamp, since I'm not an expert on patch
formats, but it looks pretty good.