This I'm not 100% sure. Should be harmless, but it's a bit subtle.
Maybe we should special-case it with "we're at the beginning of the
pattern"? Reasoning below:
The previous patch restores the performance of the original test-case.
However, if you go to the reduced test-case and try to type " re" in the
findbar, we still take a long time. The reason for that is not that the
previous patch is not effective, but that the findbar sends find
requests as soon as you type, and thus we end up with a request to find
" ", which matches a gazillion spaces in the page and causes us to use
tons of memory and time. Finding " re" is actually super-fast :-)
This fixes it, but it is a bit subtle, so thoughts? Perhaps the findbar
should wait a bit to perform the search before sending a query for " "
instead or something? But I'd rather make it fast.
Differential Revision: https://phabricator.services.mozilla.com/D111634
9f35a15d98