Move some XDG code from chrome to base.

chrome/third_party/xdg_user_dirs/xdg_user_dir_lookup.h

-/*
-  This file is not licenced under the GPL like the rest of the code.
-  Its is under the MIT license, to encourage reuse by cut-and-paste.
-
-  Copyright (c) 2007 Red Hat, inc
-
-  Permission is hereby granted, free of charge, to any person
-  obtaining a copy of this software and associated documentation files
-  (the "Software"), to deal in the Software without restriction,
-  including without limitation the rights to use, copy, modify, merge,
-  publish, distribute, sublicense, and/or sell copies of the Software,
-  and to permit persons to whom the Software is furnished to do so,
-  subject to the following conditions: 
-
-  The above copyright notice and this permission notice shall be
-  included in all copies or substantial portions of the Software. 
-
-  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
-  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
-  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
-  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
-  BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
-  ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
-  CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
-  SOFTWARE.
-*/
-
-#ifndef CHROME_THIRD_PARTY_XDG_USER_DIRS_XDG_USER_DIR_LOOKUP_H_
-#define CHROME_THIRD_PARTY_XDG_USER_DIRS_XDG_USER_DIR_LOOKUP_H_
-
-char* xdg_user_dir_lookup(const char *type);
-
-#endif  // CHROME_THIRD_PARTY_XDG_USER_DIRS_XDG_USER_DIR_LOOKUP_H_