The Inspector's Profile view currently has an "Exclude" button. But what it does is really the same as this feature from Shark: > Charge Symbol X to Callers— Removes any callstack frames containing the symbol X, and frames of functions called by X, effectively reassigning time spent in those functions to the callers. "Exclude" is a confusing name for this behavior, and will become even more confusing if "Remove Callstacks with Symbol" is added (see bug 56191), since that is another form of "exclusion".
Closing as invalid, as this bug pertains to the old inspector UI and/or its tests. Please file a new bug (https://www.webkit.org/new-inspector-bug) if the bug/feature/issue is still relevant to WebKit trunk.