Reason for revert:
Changes to frame-generator resulted in reduced fps on android and Mac on all tests.
Original issue's description:
> Reland of write frame generator capturer to use TaskQueue instead of EventTimeWrapper (patchset #1 id:1 of https://codereview.webrtc.org/2748643002/ )
>
> Reason for revert:
> Reland with fixes to the failing perf tests.
>
> Original issue's description:
> > Revert of rewrite frame generator capturer to use TaskQueue instead of EventTimeWrapper (patchset #2 id:90001 of https://codereview.webrtc.org/2744003002/ )
> >
> > Reason for revert:
> > CallPerfTest.ReceivesCpuOveruseAndUnderuse perf test fails due to this CL. It requires very accurate frame rate, which may not be so accurate now.
> >
> > Original issue's description:
> > > Reland of rewrite frame generator capturer to use TaskQueue instead of EventTimeWrapper (patchset #1 id:1 of https://codereview.webrtc.org/2743993002/ )
> > >
> > > And enable large full-stack test depending on that change (Reland of https://codereview.webrtc.org/2741823003/)
> > > TBR=stefan@webrtc.org,tommi@webrtc.org
> > > BUG=webrtc:7301,webrtc:7325
> > >
> > > Review-Url: https://codereview.webrtc.org/2744003002
> > > Cr-Commit-Position: refs/heads/master@{#17196}
> > > Committed: 8c0a5896d1
> >
> > TBR=stefan@webrtc.org,tommi@webrtc.org,sprang@webrtc.org
> > # Skipping CQ checks because original CL landed less than 1 days ago.
> > NOPRESUBMIT=true
> > NOTREECHECKS=true
> > NOTRY=true
> > BUG=webrtc:7301,webrtc:7325
> >
> > Review-Url: https://codereview.webrtc.org/2748643002
> > Cr-Commit-Position: refs/heads/master@{#17198}
> > Committed: 382a72a0d3
>
> BUG=webrtc:7301,webrtc:7325
>
> Review-Url: https://codereview.webrtc.org/2750473002
> Cr-Commit-Position: refs/heads/master@{#17253}
> Committed: 2549ad4fefTBR=sprang@webrtc.org,tommi@webrtc.org,stefan@webrtc.org
# Not skipping CQ checks because original CL landed more than 1 days ago.
BUG=webrtc:7301,webrtc:7325
Review-Url: https://codereview.webrtc.org/2751063005
Cr-Commit-Position: refs/heads/master@{#17276}
2a420ce8c4