Can you also add this to the documentation someplace (gallery?)

Please see https://github.com/matplotlib/matplotlib/wiki/MEP12, #2181 and #2474

I hope this doesn't come off the wrong way, but I don't really understand the point of this example. There are examples for bar charts and pie charts that demonstrate the functionality here, and I don't think combining the two into one plot warrants a new example.

Sorry to be so negative, but I'm of the opinion that the gallery needs to be trimmed down.

I agree with @tonysu on this.

The idea behind this example was to add more example to the Library. In my view more example we have the more useful the Library is.
@tonysyu is right with his point of view. The example does not add any new functionality but serve as an another use of this two charts types.

After reviewing the MEP12 (which @tacaswell suggested) more carefully, not to add this new example to the Library may be more reasonable to keep example sections simple and not to repeat ourselves.
In my opinion, having more and more example is quite important for useful library. On the other hand, examples should be organized carefully for usability and simplicity. ( @tonysyu is right in his point)

So, not to merge this patch will be the best.