Revert of Fixing sigslot copy constructors.

Revert of Fixing sigslot copy constructors. (patchset #3 id:40001 of https://codereview.webrtc.org/2842423002/ )

Reason for revert:
This seems to cause a heap use after free issue in Chrome:

XmppConnectionTest.ConnectThenError
XmppConnectionTest.RaisedError
XmppConnectionTest.FailureAfterPreAuth
XmppConnectionTest.PreAuthFailure
XmppConnectionTest.ImmediateFailure

https://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_tsan_rel_ng/builds/65096

Original issue's description:
> Fixing sigslot copy constructors.
> 
> They used to work, but were broken by a somewhat recent refactoring of
> sigslot.h.
> 
> It's reasonable for signals and slots to have copy constructors, since
> a class that uses signals/slots may want to be copyable.
> 
> BUG=webrtc:7342
> 
> Review-Url: https://codereview.webrtc.org/2842423002
> Cr-Commit-Position: refs/heads/master@{#17942}
> Committed: https://chromium.googlesource.com/external/webrtc/+/8b1d862bfe6b8c160b0130e7d0b0444bcf668dd4

TBR=pthatcher@webrtc.org,deadbeef@webrtc.org
# Not skipping CQ checks because original CL landed more than 1 days ago.
BUG=webrtc:7342

[perkj_webrtc, 2017-05-02 11:31:46]

The CQ bit was checked by perkj@webrtc.org

[perkj_webrtc, 2017-05-02 11:31:46]

Created Revert of Fixing sigslot copy constructors.

[commit-bot: I haz the power, 2017-05-02 11:31:52]

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, 2017-05-02 11:33:18]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2017-05-02 11:33:18]

Try jobs failed on following builders:
  ios32_sim_ios9_dbg on master.tryserver.webrtc (JOB_FAILED,
http://build.chromium.org/p/tryserver.webrtc/builders/ios32_sim_ios9_dbg/buil...)
  ios64_sim_ios10_dbg on master.tryserver.webrtc (JOB_FAILED,
http://build.chromium.org/p/tryserver.webrtc/builders/ios64_sim_ios10_dbg/bui...)
  ios_arm64_dbg on master.tryserver.webrtc (JOB_FAILED,
http://build.chromium.org/p/tryserver.webrtc/builders/ios_arm64_dbg/builds/19961)
  ios_dbg on master.tryserver.webrtc (JOB_FAILED,
http://build.chromium.org/p/tryserver.webrtc/builders/ios_dbg/builds/25273)
  mac_asan on master.tryserver.webrtc (JOB_FAILED,
http://build.chromium.org/p/tryserver.webrtc/builders/mac_asan/builds/24310)
  mac_rel on master.tryserver.webrtc (JOB_FAILED,
http://build.chromium.org/p/tryserver.webrtc/builders/mac_rel/builds/25293)

[perkj_webrtc, 2017-05-02 13:16:03]

On 2017/05/02 11:33:18, commit-bot: I haz the power wrote:
> Try jobs failed on following builders:
>   ios32_sim_ios9_dbg on master.tryserver.webrtc (JOB_FAILED,
>
http://build.chromium.org/p/tryserver.webrtc/builders/ios32_sim_ios9_dbg/buil...)
>   ios64_sim_ios10_dbg on master.tryserver.webrtc (JOB_FAILED,
>
http://build.chromium.org/p/tryserver.webrtc/builders/ios64_sim_ios10_dbg/bui...)
>   ios_arm64_dbg on master.tryserver.webrtc (JOB_FAILED,
>
http://build.chromium.org/p/tryserver.webrtc/builders/ios_arm64_dbg/builds/19961)
>   ios_dbg on master.tryserver.webrtc (JOB_FAILED,
> http://build.chromium.org/p/tryserver.webrtc/builders/ios_dbg/builds/25273)
>   mac_asan on master.tryserver.webrtc (JOB_FAILED,
> http://build.chromium.org/p/tryserver.webrtc/builders/mac_asan/builds/24310)
>   mac_rel on master.tryserver.webrtc (JOB_FAILED,
> http://build.chromium.org/p/tryserver.webrtc/builders/mac_rel/builds/25293)

Turns out that this is the offending cl:
https://codereview.webrtc.org/2846593005...

[perkj_webrtc, 2017-05-02 13:16:10]

Description was changed from

==========
Revert of Fixing sigslot copy constructors. (patchset #3 id:40001 of
https://codereview.webrtc.org/2842423002/ )

Reason for revert:
This seems to cause a heap use after free issue in Chrome:

XmppConnectionTest.ConnectThenError
XmppConnectionTest.RaisedError
XmppConnectionTest.FailureAfterPreAuth
XmppConnectionTest.PreAuthFailure
XmppConnectionTest.ImmediateFailure

https://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium...

Original issue's description:
> Fixing sigslot copy constructors.
> 
> They used to work, but were broken by a somewhat recent refactoring of
> sigslot.h.
> 
> It's reasonable for signals and slots to have copy constructors, since
> a class that uses signals/slots may want to be copyable.
> 
> BUG=webrtc:7342
> 
> Review-Url: https://codereview.webrtc.org/2842423002
> Cr-Commit-Position: refs/heads/master@{#17942}
> Committed:
https://chromium.googlesource.com/external/webrtc/+/8b1d862bfe6b8c160b0130e7d...

TBR=pthatcher@webrtc.org,deadbeef@webrtc.org
# Not skipping CQ checks because original CL landed more than 1 days ago.
BUG=webrtc:7342
==========

to

==========
Revert of Fixing sigslot copy constructors. (patchset #3 id:40001 of
https://codereview.webrtc.org/2842423002/ )

Reason for revert:
This seems to cause a heap use after free issue in Chrome:

XmppConnectionTest.ConnectThenError
XmppConnectionTest.RaisedError
XmppConnectionTest.FailureAfterPreAuth
XmppConnectionTest.PreAuthFailure
XmppConnectionTest.ImmediateFailure

https://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium...

Original issue's description:
> Fixing sigslot copy constructors.
> 
> They used to work, but were broken by a somewhat recent refactoring of
> sigslot.h.
> 
> It's reasonable for signals and slots to have copy constructors, since
> a class that uses signals/slots may want to be copyable.
> 
> BUG=webrtc:7342
> 
> Review-Url: https://codereview.webrtc.org/2842423002
> Cr-Commit-Position: refs/heads/master@{#17942}
> Committed:
https://chromium.googlesource.com/external/webrtc/+/8b1d862bfe6b8c160b0130e7d...

TBR=pthatcher@webrtc.org,deadbeef@webrtc.org
# Not skipping CQ checks because original CL landed more than 1 days ago.
BUG=webrtc:7342
==========