Move RTCAVFoundationCapturer to webrtc/api/objc.

BUG=
R=tkchin@webrtc.org

Review URL: https://codereview.webrtc.org/1559753002 .

Patch from Jon Hjelle <hjon@andyet.net>.

Cr-Original-Commit-Position: refs/heads/master@{#11348}
Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: 7ac8babbc6f2ed4b0395ecaaf153ec91d71560d5
7 files changed