Currently, when jshin check in the *.dat  files ( (android|cast|common|flutter|ios)/icudt[bl].dat )  for icu in 
chromium/deps/icu

by using

scripts/trim_data.sh

we only checked in the dat file. It is hard to debug some of the ICU data issue because what appeared in the src/third_party/icu/source/data/locales/*/*.txt file is not the same content as those in these dat file and it is very difficult to figure out what is built into these dat file by just code search. 
I think it will be beneficial to also checked in the trimmed data that build these dat files under (android|cast|common|flutter|ios)/source/data/ so we can easily figure out the reality of what is in these dat files.