Revert of Move CoreVideoFrameBuffer from webrtc/common_video/ to webrtc/sdk/objc/

Revert of Move CoreVideoFrameBuffer from webrtc/common_video/ to webrtc/sdk/objc/ (patchset #2 id:60001 of https://codereview.webrtc.org/2851563003/ )

Reason for revert:
Revert since it breaks build of internal projects

Original issue's description:
> Move CoreVideoFrameBuffer from webrtc/common_video/ to webrtc/sdk/objc/
> 
> CoreVideoFrameBuffer is Mac/iPhone specific and should be moved into
> the webrtc/sdk/objc/ folder.
> 
> BUG=None
> 
> Review-Url: https://codereview.webrtc.org/2851563003
> Cr-Commit-Position: refs/heads/master@{#17998}
> Committed: https://chromium.googlesource.com/external/webrtc/+/d41631aa274e926c4fba1600cbcfbc18020eb35a

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

[lliuu1, 2017-05-03 17:55:05]

The CQ bit was checked by lliuu@google.com

[lliuu1, 2017-05-03 17:55:06]

Created Revert of Move CoreVideoFrameBuffer from webrtc/common_video/ to
webrtc/sdk/objc/

[commit-bot: I haz the power, 2017-05-03 17:55:15]

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, 2017-05-03 17:55:16]

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

[commit-bot: I haz the power, 2017-05-03 17:55:17]

No L-G-T-M from a valid reviewer yet.
CQ run can only be started once the patch has received an L-G-T-M from a full
committer.
Even if an L-G-T-M may have been provided, it was from a non-committer,_not_ a
full super star committer.
Committers are members of the group "project-webrtc-committers".
Note that this has nothing to do with OWNERS files.