Revert of Use std::unique_ptr instead of rtc::scoped_refptr in AsyncInvoker.

Revert of Use std::unique_ptr instead of rtc::scoped_refptr in AsyncInvoker. (patchset #2 id:20001 of https://codereview.webrtc.org/2689233003/ )

Reason for revert:
The change to messagequeue.h isn't backwards compatible. Will reland after making it backwards compatible.

Original issue's description:
> Use std::unique_ptr instead of rtc::scoped_refptr in AsyncInvoker.
> 
> The AsyncClosures only ever have one thing referencing them, so they
> should be using std::unique_ptr to manage ownership. Maybe this code was
> written before std::unique_ptr was available.
> 
> BUG=None
> 
> Review-Url: https://codereview.webrtc.org/2689233003
> Cr-Commit-Position: refs/heads/master@{#16680}
> Committed: https://chromium.googlesource.com/external/webrtc/+/a5a472927bb209a053b2648d1f0b006f4c8c30ac

TBR=pthatcher@webrtc.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=None

Review-Url: https://codereview.webrtc.org/2703613006
Cr-Commit-Position: refs/heads/master@{#16683}
Committed: https://chromium.googlesource.com/external/webrtc/+/884a7284bd11e46840006e92ea8b5fe52abdde27

[Taylor Brandstetter, 2017-02-17 23:56:53]

The CQ bit was checked by deadbeef@webrtc.org

[Taylor Brandstetter, 2017-02-17 23:56:53]

Created Revert of Use std::unique_ptr instead of rtc::scoped_refptr in
AsyncInvoker.

[commit-bot: I haz the power, 2017-02-17 23:56:57]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.webrtc.org/...

[commit-bot: I haz the power, 2017-02-17 23:57:06]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1487375813288900, "parent_rev":
"8a855d6916194d4a6941417d63c2c00dd536f6fc", "commit_rev":
"884a7284bd11e46840006e92ea8b5fe52abdde27"}

[commit-bot: I haz the power, 2017-02-17 23:57:08]

Description was changed from

==========
Revert of Use std::unique_ptr instead of rtc::scoped_refptr in AsyncInvoker.
(patchset #2 id:20001 of https://codereview.webrtc.org/2689233003/ )

Reason for revert:
The change to messagequeue.h isn't backwards compatible. Will reland after
making it backwards compatible.

Original issue's description:
> Use std::unique_ptr instead of rtc::scoped_refptr in AsyncInvoker.
> 
> The AsyncClosures only ever have one thing referencing them, so they
> should be using std::unique_ptr to manage ownership. Maybe this code was
> written before std::unique_ptr was available.
> 
> BUG=None
> 
> Review-Url: https://codereview.webrtc.org/2689233003
> Cr-Commit-Position: refs/heads/master@{#16680}
> Committed:
https://chromium.googlesource.com/external/webrtc/+/a5a472927bb209a053b2648d1...

TBR=pthatcher@webrtc.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=None
==========

to

==========
Revert of Use std::unique_ptr instead of rtc::scoped_refptr in AsyncInvoker.
(patchset #2 id:20001 of https://codereview.webrtc.org/2689233003/ )

Reason for revert:
The change to messagequeue.h isn't backwards compatible. Will reland after
making it backwards compatible.

Original issue's description:
> Use std::unique_ptr instead of rtc::scoped_refptr in AsyncInvoker.
> 
> The AsyncClosures only ever have one thing referencing them, so they
> should be using std::unique_ptr to manage ownership. Maybe this code was
> written before std::unique_ptr was available.
> 
> BUG=None
> 
> Review-Url: https://codereview.webrtc.org/2689233003
> Cr-Commit-Position: refs/heads/master@{#16680}
> Committed:
https://chromium.googlesource.com/external/webrtc/+/a5a472927bb209a053b2648d1...

TBR=pthatcher@webrtc.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=None

Review-Url: https://codereview.webrtc.org/2703613006
Cr-Commit-Position: refs/heads/master@{#16683}
Committed:
https://chromium.googlesource.com/external/webrtc/+/884a7284bd11e46840006e92e...
==========

[commit-bot: I haz the power, 2017-02-17 23:57:09]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/external/webrtc/+/884a7284bd11e46840006e92e...