Reland of Move MutableDataY{,U,V} methods to I420Buffer only.

Reland of Move MutableDataY{,U,V} methods to I420Buffer only. (patchset #1 id:1 of https://codereview.webrtc.org/2354223002/ )

Reason for revert:
Downstream application now fixed.

Original issue's description:
> Revert of Move MutableDataY{,U,V} methods to I420Buffer only. (patchset #14 id:260001 of https://codereview.webrtc.org/2278883002/ )
>
> Reason for revert:
> Broke downstream application.
>
> Original issue's description:
> > Move MutableDataY{,U,V} methods to I420Buffer only.
> >
> > Deleted from the VideoFrameBuffer base class.
> >
> > BUG=webrtc:5921
> >
> > Committed: https://crrev.com/5539ef6c03c273f39fadae41ace47fdc11ac6d60
> > Cr-Commit-Position: refs/heads/master@{#14317}
>
> TBR=perkj@webrtc.org,magjed@webrtc.org,pthatcher@webrtc.org,honghaiz@webrtc.org,stefan@webrtc.org
> # Skipping CQ checks because original CL landed less than 1 days ago.
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=webrtc:5921
>
> Committed: https://crrev.com/776870a2599b8f43ad56987f9031690e3ccecde8
> Cr-Commit-Position: refs/heads/master@{#14325}

TBR=perkj@webrtc.org,magjed@webrtc.org,pthatcher@webrtc.org,honghaiz@webrtc.org,stefan@webrtc.org
# Not skipping CQ checks because original CL landed more than 1 days ago.
BUG=webrtc:5921
Committed: https://crrev.com/64ec8f826fe1d2c3cb0c8abfa7e609726cb33453
Cr-Commit-Position: refs/heads/master@{#14389}

[nisse-webrtc, 2016-09-26 06:56:58]

Created Reland of Move MutableDataY{,U,V} methods to I420Buffer only.

[nisse-webrtc, 2016-09-27 06:23:34]

The CQ bit was checked by nisse@webrtc.org

[commit-bot: I haz the power, 2016-09-27 06:23:41]

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, 2016-09-27 07:17:28]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-09-27 07:17:46]

Description was changed from

==========
Reland of Move MutableDataY{,U,V} methods to I420Buffer only. (patchset #1 id:1
of https://codereview.webrtc.org/2354223002/ )

Reason for revert:
Downstream application now fixed.

Original issue's description:
> Revert of Move MutableDataY{,U,V} methods to I420Buffer only. (patchset #14
id:260001 of https://codereview.webrtc.org/2278883002/ )
> 
> Reason for revert:
> Broke downstream application.
> 
> Original issue's description:
> > Move MutableDataY{,U,V} methods to I420Buffer only.
> >
> > Deleted from the VideoFrameBuffer base class.
> >
> > BUG=webrtc:5921
> >
> > Committed: https://crrev.com/5539ef6c03c273f39fadae41ace47fdc11ac6d60
> > Cr-Commit-Position: refs/heads/master@{#14317}
> 
>
TBR=perkj@webrtc.org,magjed@webrtc.org,pthatcher@webrtc.org,honghaiz@webrtc.o...
> # Skipping CQ checks because original CL landed less than 1 days ago.
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=webrtc:5921
> 
> Committed: https://crrev.com/776870a2599b8f43ad56987f9031690e3ccecde8
> Cr-Commit-Position: refs/heads/master@{#14325}

TBR=perkj@webrtc.org,magjed@webrtc.org,pthatcher@webrtc.org,honghaiz@webrtc.o...
# Not skipping CQ checks because original CL landed more than 1 days ago.
BUG=webrtc:5921
==========

to

==========
Reland of Move MutableDataY{,U,V} methods to I420Buffer only. (patchset #1 id:1
of https://codereview.webrtc.org/2354223002/ )

Reason for revert:
Downstream application now fixed.

Original issue's description:
> Revert of Move MutableDataY{,U,V} methods to I420Buffer only. (patchset #14
id:260001 of https://codereview.webrtc.org/2278883002/ )
>
> Reason for revert:
> Broke downstream application.
>
> Original issue's description:
> > Move MutableDataY{,U,V} methods to I420Buffer only.
> >
> > Deleted from the VideoFrameBuffer base class.
> >
> > BUG=webrtc:5921
> >
> > Committed: https://crrev.com/5539ef6c03c273f39fadae41ace47fdc11ac6d60
> > Cr-Commit-Position: refs/heads/master@{#14317}
>
>
TBR=perkj@webrtc.org,magjed@webrtc.org,pthatcher@webrtc.org,honghaiz@webrtc.o...
> # Skipping CQ checks because original CL landed less than 1 days ago.
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=webrtc:5921
>
> Committed: https://crrev.com/776870a2599b8f43ad56987f9031690e3ccecde8
> Cr-Commit-Position: refs/heads/master@{#14325}

TBR=perkj@webrtc.org,magjed@webrtc.org,pthatcher@webrtc.org,honghaiz@webrtc.o...
# Not skipping CQ checks because original CL landed more than 1 days ago.
BUG=webrtc:5921

Committed: https://crrev.com/64ec8f826fe1d2c3cb0c8abfa7e609726cb33453
Cr-Commit-Position: refs/heads/master@{#14389}
==========

[commit-bot: I haz the power, 2016-09-27 07:17:47]

Patchset 1 (id:??) landed as
https://crrev.com/64ec8f826fe1d2c3cb0c8abfa7e609726cb33453
Cr-Commit-Position: refs/heads/master@{#14389}