From health dashboard:
https://chrome-health.googleplex.com/health-plan/android-webview/memory/nexus4-svelte/

After fixing issue 762005, numbers came back with a ~5MiB in native heap, private dirty and overall pss.

The jump seems to have appeared during:
https://chrome-internal.googlesource.com/clank/internal/apps/+log/1dea579d34d772ccef3dc454ebe22e0a1e16f3a8..fc211dd0a6cff2672cb9764c46b682547bced7ec
http://test-results.appspot.com/revision_range?start=509307&end=509324&n=1000

Although data from that time might be unreliable. Not having much hope, but will try a bisect.

+benhenry, this is potentially release blocking