Revert of Add missing headers to framework umbrella header.

Revert of Add missing headers to framework umbrella header. (patchset #3 id:40001 of https://codereview.webrtc.org/2832803002/ )

Reason for revert:
this should be reported in different issue

Original issue's description:
> This CL adds RTCMTLVideoView.h and RTCCameraVideoCapturer.h to WebRTC.h
> in order to fix a build issue that comes up when using WebRTC.framework from swift code.
> 
> BUG=webrtc:7488
> 
> Review-Url: https://codereview.webrtc.org/2832803002
> Cr-Commit-Position: refs/heads/master@{#17909}
> Committed: https://chromium.googlesource.com/external/webrtc/+/ace5c8836d23dda287fe1232f94c7c3192408ddd

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=webrtc:7488

[hewwatt, 2017-04-28 06:57:01]

The CQ bit was checked by hewwatt@gmail.com

[hewwatt, 2017-04-28 06:57:02]

Created Revert of Add missing headers to framework umbrella header.

[commit-bot: I haz the power, 2017-04-28 06:57:11]

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, 2017-04-28 06:57:12]

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

[commit-bot: I haz the power, 2017-04-28 06:57:13]

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.