The cells are stored on prototypes (in their map's PrototypeInfo). When a prototype object changes its map, then both its own validity cell and those of all "downstream" prototypes are invalidated; handlers for a given receiver embed the currently valid cell for that receiver's prototype during their compilation and check it on execution.

Review URL: https://codereview.chromium.org/908213002

Cr-Commit-Position: refs/heads/master@{#27845}