The cronet bots (https://build.chromium.org/p/chromium.android/waterfall?builder=Android+Cronet+ARM64+Builder&builder=Android+Cronet+ARM64+Builder+%28dbg%29&builder=Android+Cronet+ARMv6+Builder&builder=Android+Cronet+Builder+%28dbg%29&builder=Android+Cronet+Builder+Asan&builder=Android+Cronet+Data+Reduction+Proxy+Builder&builder=Android+Cronet+KitKat+Builder&builder=Android+Cronet+Lollipop+Builder&builder=Android+Cronet+MIPS+Builder&builder=Android+Cronet+Marshmallow+64bit+Builder&builder=Android+Cronet+Marshmallow+64bit+Perf&builder=Android+Cronet+x86+Builder&builder=Android+Cronet+x86+Builder+%28dbg%29&reload=none) aren't tree closers, but they do have gatekeeper emails set up. When there's a failure, the emails say something like "Automatically closing tree for "compile,steps" on "Android Cronet ARMv6 Builder"" at the top. This sometimes confuses people.

This isn't a recent bug; I think it's been true for as long as we've had gatekeeper set up for cronet.