Verification — bi-12-debugging-tracing

A module is complete when these pass against measured or observed output, not when the prose has been read.

  • Thread census captured from thread backtrace all
  • Breakpoints at DOM creation, style recalc, layout, paint; call-stack chain recorded
  • Three unfamiliar trace event names found in source
  • Own TRACE_EVENT added, target rebuilt, event observed
  • A DCHECK deliberately violated and observed firing, then restored

Gate (§44) — for every source-reading exercise in this module

  • Why does this code exist?
  • What invariant does it maintain?
  • Who calls it?
  • What does it call?
  • Which process and thread executes it?
  • What happens if it is removed?
  • How is it tested?
  • What simpler design would fail, and why?

Record