SpeechRecognitionEngine takes in a language and the default Accept-Language header, and doesn't handle changes in either of them (It used to handle changes in the header, but I removed that, to work with the network service).

Perhaps we should support changing them, based on when the local locale/Accept-Language configuration changes?  I'm not sure how often that happens.

Filed based on comment in https://chromium-review.googlesource.com/c/chromium/src/+/1151650