Implemented an analogue of the cpu_usage metrics from third_party/webrtc/video/video_analyzer.h for third_party/webrtc/test/pc/e2e/analyzer/video/default_video_quality_analyzer.h Bug: webrtc:11496 Change-Id: Ifdc9daa3351f1df5db98beb8f7dc7156fc7c2a16 Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/174020 Reviewed-by: Artem Titov <titovartem@webrtc.org> Cr-Commit-Position: refs/heads/master@{#31141}