Even though the flight of the bumblebee is mostly written using choromatic passages, there are still enough important tones to understand which key it is written in, the other notes being tensions.
You can't really find a tune that's written "really" on the Chromatic scale, unless it is an exercice, like in dodecaphonism, where every note of the chromatic has to be played to be used again.
When you use a "chromaticism" you actually go from a scale tone to another scale tone using a "tension", that's used quite a lot in be-bop. You don't really use the chromatic scale, otherwise that would mean no tone is more important than another.