Reason for revert:
Relanding after fixing issues with no video.
Original issue's description:
> Revert of Injectable Obj-C video codecs (patchset #2 id:370001 of https://codereview.webrtc.org/2979983002/ )
>
> Reason for revert:
> Still having problems with no video. Reverting.
> Once no video is visible, no video is available from then on even if the callee app is in the foreground.
>
>
> Original issue's description:
> > Reland of Injectable Obj-C video codecs (patchset #1 id:1 of https://codereview.webrtc.org/2979973002/ )
> >
> > Reason for revert:
> > Fix the broken build file
> >
> > Original issue's description:
> > > Revert of Injectable Obj-C video codecs (patchset #3 id:400001 of https://codereview.webrtc.org/2981583002/ )
> > >
> > > Reason for revert:
> > > Breaks bots. Build file incorrect.
> > >
> > > Original issue's description:
> > > > Reland of Injectable Obj-C video codecs (patchset #1 id:1 of https://codereview.webrtc.org/2975963002/ )
> > > >
> > > > Reason for revert:
> > > > New CL for fixing the issues
> > > >
> > > > Original issue's description:
> > > > > Revert of Injectable Obj-C video codecs (patchset #8 id:140001 of https://codereview.webrtc.org/2966023002/ )
> > > > >
> > > > > Reason for revert:
> > > > > Causes no video in certain scenarios. Please come up with a test plan or unit test to prevent such problems in the future.
> > > > >
> > > > > Original issue's description:
> > > > > > Injectable Obj-C video codecs
> > > > > >
> > > > > > Initial CL for this effort, with a working RTCVideoEncoder/Decoder for H264
> > > > > > (wrapping the VideoToolbox codec).
> > > > > >
> > > > > > Some notes / things left to do:
> > > > > > - There are some hard-coded references to codec types that are supported by
> > > > > > webrtc::VideoCodec, cricket::VideoCodec, webrtc::CodecSpecificInfo etc
> > > > > > since we need to convert to/from these types in ObjCVideoEncoder/Decoder.
> > > > > > These types would need to be more codec agnostic to avoid this.
> > > > > > - Most interfaces are borrowed from the design document for injectable
> > > > > > codecs in Android. Some data in the corresponding C++ classes is discarded
> > > > > > when converting to the Obj-C version, since it has fewer fields. I have not
> > > > > > verified whether all data that we do keep is needed, or whether we might be
> > > > > > losing anything useful in these conversions.
> > > > > > - Implement the VideoToolbox codec code directly in the RTCVideoEncoderH264
> > > > > > classes, instead of wrapping webrtc::H264VideoToolboxEncoder / decoder.
> > > > > > Eliminates converting between ObjC/C++ types outside the ObjCVideoEncoder/
> > > > > > Decoder wrapper classes.
> > > > > > - List the injected codec factory's supported codecs in the list of codecs in
> > > > > > AppRTCMobile.
> > > > > >
> > > > > > BUG=webrtc:7924
> > > > > > R=magjed@webrtc.org
> > > > > >
> > > > > > Review-Url: https://codereview.webrtc.org/2966023002 .
> > > > > > Cr-Commit-Position: refs/heads/master@{#18928}
> > > > > > Committed: a0349c138d
> > > > >
> > > > > TBR=magjed@webrtc.org,andersc@webrtc.org
> > > > > # Not skipping CQ checks because original CL landed more than 1 days ago.
> > > > > BUG=webrtc:7924
> > > > > NOTRY=true
> > > > >
> > > > > Review-Url: https://codereview.webrtc.org/2975963002
> > > > > Cr-Commit-Position: refs/heads/master@{#18979}
> > > > > Committed: 1095ada7ad
> > > >
> > > > R=magjed@webrtc.org
> > > > TBR=tkchin@webrtc.org
> > > > # Skipping CQ checks because original CL landed less than 1 days ago.
> > > > NOPRESUBMIT=true
> > > > NOTREECHECKS=true
> > > > NOTRY=true
> > > > BUG=webrtc:7924
> > > >
> > > > Review-Url: https://codereview.webrtc.org/2981583002 .
> > > > Cr-Commit-Position: refs/heads/master@{#19002}
> > > > Committed: a5f1de1e65
> > >
> > > TBR=magjed@webrtc.org,tkchin@webrtc.org,jtteh@webrtc.org,andersc@webrtc.org
> > > # Skipping CQ checks because original CL landed less than 1 days ago.
> > > NOPRESUBMIT=true
> > > NOTREECHECKS=true
> > > NOTRY=true
> > > BUG=webrtc:7924
> > >
> > > Review-Url: https://codereview.webrtc.org/2979973002
> > > Cr-Commit-Position: refs/heads/master@{#19004}
> > > Committed: 81d40ee149
> >
> > TBR=magjed@webrtc.org,tkchin@webrtc.org,jtteh@webrtc.org,sprang@webrtc.org
> > BUG=webrtc:7924
> >
> > Review-Url: https://codereview.webrtc.org/2979983002
> > Cr-Commit-Position: refs/heads/master@{#19005}
> > Committed: 732a3437da
>
> TBR=magjed@webrtc.org,tkchin@webrtc.org,sprang@webrtc.org,haysc@webrtc.org,andersc@webrtc.org
> # Not skipping CQ checks because original CL landed more than 1 days ago.
> BUG=webrtc:7924
>
> Review-Url: https://codereview.webrtc.org/2980173002
> Cr-Commit-Position: refs/heads/master@{#19036}
> Committed: 860f729816TBR=magjed@webrtc.org,tkchin@webrtc.org,sprang@webrtc.org,haysc@webrtc.org,andersc@webrtc.org,jtteh@webrtc.org
# Not skipping CQ checks because original CL landed more than 1 days ago.
BUG=webrtc:7924
Review-Url: https://codereview.webrtc.org/2977213002
Cr-Commit-Position: refs/heads/master@{#19135}
fb143127d7