Revert of NaCl cleanup: Split out irt_interfaces.cc from irt_ppapi.cc

Revert of NaCl cleanup: Split out irt_interfaces.cc from irt_ppapi.cc (patchset #1 id:1 of https://codereview.chromium.org/1244533006/)

Reason for revert:
Regressed Linux sizes - 4.5% is a bit of a hit to take to bump sizes. If you're absolutely sure this is acceptable, update sizes as well.

Original issue's description:
> NaCl cleanup: Split out irt_interfaces.cc from irt_ppapi.cc
>
> The intention here is that irt_interfaces.{cc,h} should list the NaCl
> IRT interfaces that we implement in Chromium but that other files
> (like irt_ppapi.cc) should implement them.  This matches how the files
> are organised in native_client/src/untrusted/irt/.
>
> This is in preparation for copying the PNaCl translator IRT interfaces
> to the Chromium side.  That will add a couple more interfaces to
> irt_interfaces.cc (rather than to irt_ppapi.cc).
>
> BUG=302078
> TEST=NaCl tests in browser_tests
>
> Committed: https://crrev.com/5e662010c1f7881970de6de19bcbd50f2726ea00
> Cr-Commit-Position: refs/heads/master@{#339508}

TBR=jvoung@chromium.org,bbudge@chromium.org,mseaborn@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=302078
Committed: https://crrev.com/db9f0a6b277a39d2f2b70d99e17801a18a6d79a6
Cr-Commit-Position: refs/heads/master@{#339559}

[Ryan Sleevi, 2015-07-20 23:24:30]

Created Revert of NaCl cleanup: Split out irt_interfaces.cc from irt_ppapi.cc

[commit-bot: I haz the power, 2015-07-20 23:25:59]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1249473003/1

[commit-bot: I haz the power, 2015-07-20 23:28:03]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-07-20 23:29:44]

Patchset 1 (id:??) landed as
https://crrev.com/db9f0a6b277a39d2f2b70d99e17801a18a6d79a6
Cr-Commit-Position: refs/heads/master@{#339559}

[Mark Seaborn, 2015-07-21 04:51:20]

A revert of this CL (patchset #1 id:1) has been created in
https://codereview.chromium.org/1245893002/ by mseaborn@chromium.org.

The reason for reverting is: The size increase was caused by a Skia DEPS roll
(https://codereview.chromium.org/1245793002/), not by this change..

[Matt Giuca, 2015-07-21 07:50:08]

I filed a bug about this regression, please keep it updated:
http://crbug.com/512342.