All graphs for this bug:
  https://chromeperf.appspot.com/group_report?bug_id=733980

Original alerts at time of bug-filing:
  https://chromeperf.appspot.com/group_report?keys=agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgIDg5vGkvgoM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgIDgpu6cqgkM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgIDg5q7epgoM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgIDg5sCJ_AoM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgIDg5rG_rwoM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgIDg5rHrtgoM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgIDg5o6QpwsM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgIDg5oqF_AgM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgIDg5s6WtQoM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgIDghuG4iQgM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgIDg5pzWvQoM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgIDgpvP5twoM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgIDg5qy9pwoM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgIDgptXurQoM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgIDgpuWTuwoM


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

webrtc-android-tests-nexus5-kitkat

It looks similar to https://bugs.chromium.org/p/chromium/issues/detail?id=733554.

Chromium recently switched from gcc to clang for android (https://chromium.googlesource.com/chromium/src/build/+/5a7ba0fdfa1c5c98291d5a66f5d2a085051de215) and this can cause a perf regression (see  crbug.com/481675 ).

I think this is the root cause. Let me know if you want more investigation.

I don't think that's the case here. The roll doesn't appear to contain the gcc -> clang change.

However, I agree that it isn't worth spending too much time on.