Revert 63600 - Thread IO safety: annotate file_util, and block IO thread from doing IO

Reverting because this breaks the ChromiumOS (dbg) builder.

- Mark functions in file_util_posix as requiring permission to perform
  disk actions.
- Mark the IO thread as disallowed from performing disk actions.
- Temporarily work around the protections in places where we currently
  have bugs.

BUG=59847,59849,60207,60211
TEST=no dchecks in debug builds

Review URL: http://codereview.chromium.org/3872002

TBR=evan@chromium.org
Review URL: http://codereview.chromium.org/3983005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@63630 0039d316-1c4b-4281-b951-d872f2087c98
13 files changed