Revert 239280 "Move more file_util functions to base namespace."

dbus_unittests started fialing on Linux Tests (dbg)(2) and Linux Tests (dbg)(2)(32).
This CL is the only in the intersection of CLs in the first failing build on
the two builders, so giving a speculative revert a try (rlarocque already
tried a clobber, it didn't help).

http://build.chromium.org/p/chromium.linux/builders/Linux%20Tests%20%28dbg%29%282%29/builds/41806
http://build.chromium.org/p/chromium.linux/builders/Linux%20Tests%20%28dbg%29%282%29%2832%29/builds/8544


> Move more file_util functions to base namespace.
> 
> TBR=sky
> 
> Review URL: https://codereview.chromium.org/109043002

TBR=brettw@chromium.org

Review URL: https://codereview.chromium.org/105823009

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@239400 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 239400