Use one scoped_refptr.

Use one scoped_refptr.

Uses webrtc/base/scoped_ref_ptr.h and removes the copy in
system_wrappers.

BUG=
R=kwiberg@webrtc.org, tommi@webrtc.org

Committed: https://crrev.com/26b08605e2b99136fcc1cab0800234f469d6e236
Cr-Commit-Position: refs/heads/master@{#9370}

[pbos-webrtc, 2015-06-04 09:34:17]

remove from BUILD.gn

[pbos-webrtc, 2015-06-04 09:35:31]

PTAL :)

[tommi, 2015-06-04 10:38:31]

Can't review right now but rs lgtm fwiw. Can you get someone else to give it a
once over?

[pbos-webrtc, 2015-06-04 11:34:25]

pbos@webrtc.org changed reviewers:
+ kwiberg@webrtc.org

[pbos-webrtc, 2015-06-04 11:34:26]

Sure. +R kwiberg@

[kwiberg-webrtc, 2015-06-04 12:27:36]

lgtm

[pbos-webrtc, 2015-06-04 13:18:34]

Committed patchset #2 (id:20001) manually as
26b08605e2b99136fcc1cab0800234f469d6e236 (presubmit successful).

[commit-bot: I haz the power, 2015-06-05 12:05:17]

Patchset 2 (id:??) landed as
https://crrev.com/26b08605e2b99136fcc1cab0800234f469d6e236
Cr-Commit-Position: refs/heads/master@{#9370}