public SoundData getSoundData(String name) {
        return mSoundDataMap.get(name);
    }
This function takes a map of keys to sounds and creates SoundData objects
to prefetch the data before storing them in a local map. We currently only
support external urls (web-based).

@param soundMap a map of String keys to String url's.
android/viro_bridge/src/main/java/com/viromedia/bridge/module/SoundModule.java