Add an unpatched version of xz, XZ Utils, to /trunk/deps/third_party.

README.chromium will be placed in the Chromium tree in the directory that
receives xz. Here are its contents, which provide information about xz:

Name: XZ Utils
Source URL: git://
Version: git commit c15c42abb3c8c6e77c778ef06c97a4a10b8b5d00
         (2010-06-15 14:06:29 +0300), newer than 4.999.9beta
License: Public domain/license grant, LGPL 2.1, GPL 2, GPL 3
License File: COPYING

XZ Utils is general-purpose data compression software implementing the
modified Lempel-Ziv-Markov chain algorithm (LZMA2).

Local Modifications:
 - None.

Review URL:

git-svn-id: 4ff67af0-8c30-449e-8e8b-ad334ec8d88c
340 files changed