The current find-in-page implementation stores in the main frame a pointer to the frame holding the current active match. However, it does not handle the situations where this frame is destroyed. This pointer and the active match range need to be properly invalidated if the frame is not reachable anymore.
Marked LayoutTest bugs, bugs with Chromium IDs, and some others as WontFix. Test failure bugs still are trackable via TestExpectations or disabled unit tests.