Revert of Delete method cricket::VideoFrame::Copy. (patchset #3 id:210001 of https://codereview.webrtc.org/2275243002/ )

Reason for revert:
Again, brakes a downstream build by removing VideoFrame::Copy method.

Original issue's description:
> Reland of Delete method cricket::VideoFrame::Copy. (patchset #1 id:1 of https://codereview.webrtc.org/2087923004/ )
>
> Reason for revert:
> Downstream issue now fixed.
>
> Original issue's description:
> > Revert of Delete method cricket::VideoFrame::Copy. (patchset #7 id:120001 of https://codereview.webrtc.org/2080253002/ )
> >
> > Reason for revert:
> > It broke a downstream build by removing VideoFrame::Copy method.
> >
> > Original issue's description:
> > > Delete method cricket::VideoFrame::Copy.
> > >
> > > Should be unused in Chrome since cl
> > > https://codereview.chromium.org/2068703002/
> > >
> > > TBR=tkchin@webrtc.org,magjed@webrtc.org
> > > BUG=webrtc:5682
> > >
> > > Committed: https://crrev.com/9c00f646f0b3cd33506a1944c7bc6724af041237
> > > Committed: https://crrev.com/7e4e00d189a5dfac2b463a5100ee65ee2f11ed79
> > > Cr-Original-Commit-Position: refs/heads/master@{#13236}
> > > Cr-Commit-Position: refs/heads/master@{#13244}
> >
> > TBR=pbos@webrtc.org,tkchin@webrtc.org,magjed@webrtc.org,sergeyu@chromium.org,nisse@webrtc.org
> > # Skipping CQ checks because original CL landed less than 1 days ago.
> > NOPRESUBMIT=true
> > NOTREECHECKS=true
> > NOTRY=true
> > BUG=webrtc:5682
> >
> > Committed: https://crrev.com/123f33cd009606d22cca8b0f4756812406d4580f
> > Cr-Commit-Position: refs/heads/master@{#13246}
>
> TBR=pbos@webrtc.org,tkchin@webrtc.org,magjed@webrtc.org,sergeyu@chromium.org,honghaiz@webrtc.org
> # Not skipping CQ checks because original CL landed more than 1 days ago.
> BUG=webrtc:5682
>
> Committed: https://crrev.com/f715f983f1b33208ab2d2434f8b36ad5271f680f
> Cr-Commit-Position: refs/heads/master@{#13924}

TBR=pbos@webrtc.org,tkchin@webrtc.org,magjed@webrtc.org,sergeyu@chromium.org,honghaiz@webrtc.org,nisse@webrtc.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=webrtc:5682

Review-Url: https://codereview.webrtc.org/2275313003
Cr-Original-Commit-Position: refs/heads/master@{#13925}
Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: 91b03b0ff8c480e4245835c7a4a93733aac534a6
1 file changed