Delete video_quality_measurement. We don't use it and we don't plan on using it. BUG=none Review-Url: https://codereview.webrtc.org/3005993002 Cr-Original-Commit-Position: refs/heads/master@{#19655} Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc Cr-Mirrored-Commit: 83e887cdcbd94b6fe54c40ea790761af9a3d3d43