Revert of Mojo: Convert some scoped_ptr<...>(new ...) to make_scoped_ptr(new ...) in mojo/{embedder,system}.

Revert of Mojo: Convert some scoped_ptr<...>(new ...) to make_scoped_ptr(new ...) in mojo/{embedder,system}. (patchset #2 id:20001 of https://codereview.chromium.org/610083002/)

Reason for revert:
scoped_ptr nullptr support was reverted.

Original issue's description:
> Mojo: Convert some scoped_ptr<...>(new ...) to make_scoped_ptr(new ...) in mojo/{embedder,system}.
>
> R=jamesr@chromium.org
>
> Committed: https://crrev.com/a60566701028a7344d17826076780eeb84b63052
> Cr-Commit-Position: refs/heads/master@{#297095}

TBR=jamesr@chromium.org,viettrungluu@chromium.org
NOTREECHECKS=true
NOTRY=true

Committed: https://crrev.com/3f8f6ea2347da4437dfd56b567c7daddfb9d8940
Cr-Commit-Position: refs/heads/master@{#297108}

[dcheng, 2014-09-27 07:42:19]

Created Revert of Mojo: Convert some scoped_ptr<...>(new ...) to
make_scoped_ptr(new ...) in mojo/{embedder,system}.

[viettrungluu, 2014-09-29 16:50:00]

A revert of this CL (patchset #1 id:1) has been created in
https://codereview.chromium.org/613673004/ by viettrungluu@chromium.org.

The reason for reverting is: scoped_ptr nullptr support was un-reverted..