Revert "Added support for NaCl IO to use the IRT Extension API."

Revert "Added support for NaCl IO to use the IRT Extension API."

This reverts commit 3183230ac54a9b443f6e67a64121a0c3ee734e6b.

There is some subtle behavior when certain interfaces are not available,
and how libnacl falls-back to other interfaces.

For example, the fdio interface is not available on PNaCl, but the
fdio-dev interface is.  libnacl has an early fallback that attempts to
query fdio, and if it is not available, will fill in its fdio interface
struct with the fdio-dev pointers. This logic is necessary to get output
to the Chrome console. In kernel_wrap_newlib, this behavior is preserved
because the "real" pointers are grabbed directly from the newlib
structures. In The IRT extension API, this fails because it queries the
interfaces directly.

If we query the interface pointers directly, we'll have to reimplement
the fall-back logic. Perhaps this is worth doing, but the IRT extension
API is still not implemented for glibc, so the benefits of it are
minimal at this point.

BUG=http://crbug.com/472185
R=sbc@chromium.org
CC=dyen@chromium.org

Committed: https://crrev.com/8c7a8d9ac7b85e64f69df7956c461122057bad91
Cr-Commit-Position: refs/heads/master@{#323260}

[binji, 2015-04-01 00:16:52]

The CQ bit was checked by binji@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2015-04-01 00:17:09]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1046323002/1

[Sam Clegg, 2015-04-01 00:20:59]

lgtm (reverted without any conflicts?)

[commit-bot: I haz the power, 2015-04-01 00:58:51]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-04-01 00:58:52]

This issue passed the CQ dry run.

[binji, 2015-04-01 16:52:18]

On 2015/04/01 00:20:59, Sam Clegg wrote:
> lgtm (reverted without any conflicts?)

yep!

[binji, 2015-04-01 16:52:24]

The CQ bit was checked by binji@chromium.org

[commit-bot: I haz the power, 2015-04-01 16:52:42]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1046323002/1

[commit-bot: I haz the power, 2015-04-01 16:54:01]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-04-01 16:55:00]

Patchset 1 (id:??) landed as
https://crrev.com/8c7a8d9ac7b85e64f69df7956c461122057bad91
Cr-Commit-Position: refs/heads/master@{#323260}