Caused by “Add MaybeValid() to base::Callback”

Commit: 40f8e9a571636737228190af5a062869dbf028d4

Debugging size regressions is documented at: https://chromium.googlesource.com/chromium/src/+/master/docs/speed/apk_size_regressions.md#Debugging-Apk-Size-Increase

Based on the graph: Native code growth.

This is quite old now since we missed the alert originally as it was part of a roll but I thought I'd file a bug given there was some discussion on the original CL regarding size concerns.