Revert of Init Mojo embedder for Windows NaCl plugins.

Revert of Init Mojo embedder for Windows NaCl plugins. (patchset #6 id:160001 of https://codereview.chromium.org/1044953003/)

Reason for revert:
MojoFailsWithoutFlag fails on windows bots, as reported by sergeyu (weirdly, this passed in the CQ)

Original issue's description:
> Init Mojo embedder for Windows NaCl plugins.
>
> With this change (and another fix for NACL_BUILD_SUBARCH), we can test
> Pepper/Mojo/NaCl support on Windows.
>
> This also moves embedder initialization to nacl_helper for clarity:
> The Mojo embedder must be initialized in nacl_helper when that process
> is used. When the plugin is running in a chrome process, ContentMain()
> handles Mojo embedder initialization.
>
> BUG=414804
> R=dmichael@chromium.org, ncbray@chromium.org
>
> Committed: https://chromium.googlesource.com/chromium/src/+/75386dca6ebff785e62eb52472e660c757d5b2e8

TBR=ncbray@chromium.org,dmichael@chromium.org,sergeyu@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=414804
Committed: https://crrev.com/78dffa27e6472ea500d73f9d7d695f7ecac0a5c5
Cr-Commit-Position: refs/heads/master@{#323793}

[teravest, 2015-04-03 19:25:24]

Created Revert of Init Mojo embedder for Windows NaCl plugins.

[commit-bot: I haz the power, 2015-04-03 19:25:37]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1053313002/1

[commit-bot: I haz the power, 2015-04-03 19:26:31]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-04-03 20:40:00]

Patchset 1 (id:??) landed as
https://crrev.com/78dffa27e6472ea500d73f9d7d695f7ecac0a5c5
Cr-Commit-Position: refs/heads/master@{#323793}