Aaah I see what I was doing wrong.
turns out that a CL
that landed right after the roll range, happened to fix the root cause of the issue.
I was just checking out third_party/perfetto @ origin/master assuming the root cause was still there in our ToT.
Your comment, where you did the right thing by checking out precisely the version that failed, shows that. I can repro as well if checkout the roll revision as you did.
I think this is what happened:
1. The roll passed the CQ because the CQ doesn't build "all" but builds only the affected target from gn analyze. The problem here is the addition of a spurious library to the build graph which is not referred by any chrome target, but fails only when built in isolation, which really shows up with :all.
2. I think (didn't check) the main waterfall didn't go red because there is no bot there that covers the combination of is_debug && is_component && is_android (this seems to fail only in component builds)
Also I think that the mysterious lld error really meant "you are trying to build a shared library, but there are no source files in it"
I think we can call it mystery solved.