Caused by "Add a mojo channel for frame messages."
9d46ef7db2e30e99230aaf9584723a9dab06a2d3

Link to size graph: https://chromeperf.appspot.com/report?sid=a097e74b1aa288511afb4cb616efe0f95ba4d347ad61d5e835072f23450938ba&rev=475079

How to debug this size regressions is documented at: https://chromium.googlesource.com/chromium/src/+/master/tools/perf/docs/apk_size_regressions.md#Debugging-Apk-Size-Increase

Adds mojo and looks like a decent sized change, so my guess is that this growth is expected. Feel free to close as "Won't Fix".

Hopefully we will claw back some of the size when we remove the Chrome IPC.