The CL is https://codereview.chromium.org/2724983003.

[+dfalcantara@ as an OWNER of content/public/android/java/res/]

1) What is your view on this?
2) How much of this reduction affects .apk size? .*java/res/.* only?
3) I believe the reduction is lossless, am I right? If yes, TBR must be fine?
4) Should I proceed and run the command in parallel over entire repository?
If yes, should I divide results into multiple CLs?

1) I only have an opinion on the Android resources.  We're usually good at remembering to ask people to optimize their PNG files when Android reviews come up, so I'm not surprised that we don't get much extra savings there.

2) In the past, we've compiled specific PAK files with the bitmaps from the non-Android resource directories, but I can't think of which directories off the top of my head.  They were listed in one of the GRD files, IIRC.

3) No, don't TBR.  IIRC there were some files the script glitched on and we had to revert them.  It required manual inspection to make sure the resources still looked right.

4) I wouldn't do that without asking chromium-dev about it.  I'm not sure who added the script initially and not sure if it was specifically for Android.