All graphs for this bug:
  https://chromeperf.appspot.com/group_report?bug_id=733547

Original alerts at time of bug-filing:
  https://chromeperf.appspot.com/group_report?keys=agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgIDgtsOu4AsM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgIDgtryKkgoM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgIDgttXb5QoM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgIDgtueurQoM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgIDgtvi6rAsM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgIDgtpW08woM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgIDgtpPzrQkM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgIDgtrHEtwkM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgIDg1rbxkAoM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgIDg1vaKjQsM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgIDglre3gQkM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgIDg1qGytwsM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgIDgtpLJsAsM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgIDgtpLC_wgM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgIDg1qzekgkM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgIDg1pad5QkM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgIDg1r3IuQkM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgIDg1o6RtwoM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgIDglo-X5gkM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgIDg1sib-gsM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgIDg1p_9pgsM


Bot(s) for this bug's original alert(s):

webrtc-android-tests-nexus5-kitkat
webrtc-linux-large-tests
webrtc-mac-large-tests
webrtc-win-large-tests

I have looked at the changes to VP8, and it looks like the nexus5 kitkat bot is very unstable, these values change fairly frequently. Also looked at other bots and couldn't see any change to VP8 for these metrics, so I will ignore them.