Defines a streaming speech recognizer API. It provides access to the platform speech recognition service.
Note that there can be only one speech recognizer. Attempting to create a second speech recognizer without destroying the first one will result in undefined behavior.
SbSpeechRecognizerDestroy should be called from a single thread. Callbacks defined in
SbSpeechRecognizerHandler will happen on another thread, so calls back into the SbSpeechRecognizer from the callback thread are disallowed.