FYI, there's also a Put call a little later in this function: http://searchfox.org/mozilla-central/rev/fee636af734a0ce6dc7335691cc94664bafc385d/dom/webbrowserpersist/nsWebBrowserPersist.cpp#2730,2732,2767 I guess we could replace that by using LookupForAdd instead of Get, but there are some interleaving returns (NS_ENSURE_SUCCESS) that makes that tricky. I wonder if it would be worth adding a "dead-mans-switch" thingy to EntryPtr that would automatically Remove any new entry in the dtor, unless OrInsert was called... (Could have used that in 1370674 to avoid the manual Removes.) Anyway, I don't expect this method to be very hot though...

(Filed bug 1372333 on adding a Remove() method, automatic or not)

Pushed by mpalmgren@mozilla.com: https://hg.mozilla.org/integration/mozilla-inbound/rev/2fe892847030 Remove a redundant hashtable Contains call. r=froydnj