#47171 migrated `std::deque` to `base::circular_deque` in
`shell/common/crash_keys.cc`. However, `CrashKeyString` wraps a
`crashpad::Annotation` that holds self-referential pointers and
registers itself in a process-global linked list. `circular_deque`
relocates elements on growth (via `VectorBuffer::MoveConstructRange`),
leaving those pointers dangling — causing missing crash keys or a hung
crashpad handler (especially on macOS). The `base/containers/README.md`
warns: "Since `base::deque` does not have stable iterators and it will
move the objects it contains, it may not be appropriate for all uses."
Reverts to `std::deque`, whose block-based layout never relocates
existing elements. Adds a regression test that registers 50 dynamic
crash keys and verifies they all survive a renderer crash.
Notes: Fixed crash keys being lost and the crash reporter hanging on
macOS when many dynamic crash keys were registered.
Made-with: Cursor
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