It seems that enabling ThinLTO was actually a binary size regression for Chrome.apk, which stores the natively library compressed.

The compression ratio for libchrome.so went from 41% in M70 to 37% in M71. Although libchrome.so shrank by ~380kb, its compressed size went from 27628495->28221029 (an increase of 590kb).

Given that:
* We compress the library for only one of our apks
* The library gets extracted anyways (so on-disk regression is only 590-380=210kb
* LTO has significant runtime improvements

I think it makes sense to live with the regression, but wanted to let everyone know that this happened in case anyone has insights into mitigating it.