23c564b7e1
Even if `<datalist>` is dynamically changed, autocomplete controller still uses previous search result. If changed, we have to ignore previous result that may be invalid. Also, even if `<datalist>` is changed, we have to keep selected index (Bug 595069), so we cannot use `ResetInternalState` at this situation. It resets selected index. Differential Revision: https://phabricator.services.mozilla.com/D116679