We incur a noticeable amount of overhead on some benchmarks due to checking if the Watchdog ever fired. There is no reason to do this checking if we never activated the Watchdog, which can only be done through JSContextGroupSetExecutionTimeLimit or JSContextGroupClearExecutionTimeLimit. By allocating the Watchdog lazily on the VM we can avoid all of the associated overhead when we don't use these two API functions (which is true of most clients).
Created attachment 231793 [details] Patch
Comment on attachment 231793 [details] Patch r=me
Comment on attachment 231793 [details] Patch Clearing flags on attachment: 231793 Committed r169139: <http://trac.webkit.org/changeset/169139>
All reviewed patches have been landed. Closing bug.