From the Chromium mailing list:
TL;DR - 32 bit is no more (?)

Hi, chromium devs,

TL:DR;
I will remove following 4 builders next week.
Linux Builder (dbg)(32)
Linux Tests (dbg)(1)(32)
linux_chromium_compile_dbg_32_ng
linux_chromium_dbg_32_ng

More explanation:
For now, chromium does not support 32 bit Linux
https://support.google.com/chrome/...
and all 32 bit x86 devices for chromeos is EOL too.
https://chromium.org/chromium-os/...

Considering that, I was not able to find any reason we have builders for not supported platform now.
If you have any comments about this builder removal, please let me know.
I will start removing process of the builders next week if there is no concern from you.

Note: This removal does not include 32 bit android/windows/libfuzzer or other than chromium builders.

Thanks,
Takuto

--
Takuto Ikuta
Software Engineer in Tokyo
Chrome Ops (goma team)