Revert "Add framesRendered to StatsReport"

This reverts commit dcfa938f9e768d463d3e336f4d014027504267dd.

Reason for revert: This CL blocks rolling WebRTC into chromium

Original change's description:
> Add framesRendered to StatsReport
> 
> Bug: webrtc:9568
> Change-Id: I6976f4c48b67f6a81f57260a91966debbef38eb4
> Reviewed-on: https://webrtc-review.googlesource.com/90840
> Reviewed-by: Steve Anton <steveanton@webrtc.org>
> Commit-Queue: Steve Anton <steveanton@webrtc.org>
> Cr-Commit-Position: refs/heads/master@{#24121}

TBR=steveanton@webrtc.org,solenberg@webrtc.org,joachimr@fb.com

Change-Id: Ia58feefd0ab557bb39ff79840dc8fa5004fee753
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: webrtc:9568
Reviewed-on: https://webrtc-review.googlesource.com/90900
Reviewed-by: Artem Titov <titovartem@webrtc.org>
Commit-Queue: Artem Titov <titovartem@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#24134}