Good catch--I forgot all about this. Path simplification doesn't supersede this, however. It can still make the difference between being able make a plot, and not. Here is an example:

import numpy as np
import matplotlib.pyplot as plt
xx = np.random.randn(1000000)
yy = np.ma.array(xx)
yy[::3] = np.ma.masked
plt.plot(yy)  # fails
plt.rcParams['agg.path.chunksize'] = 20000
plt.plot(yy) # succeeds

Maybe the thing to do, in the interest of simplification, is to remove the rcParam and hardwire a suitable chunksize. @mdboom, is there a better way of avoiding the agg limitation?

Ah, sorry I misunderstood your comment.

@efiring: No -- unfortunately, the limit is a compile-time constant in Agg.

There's a test case for the chunking in #8176, so it does seem to work; is its non-use the only reason for removing it?