Fix CPDF_ICCBasedCS::GetDefaultValue heap-buffer-overflow.

Introduced in ea44bd0.  Re-animating the dead (code) usually turns
out badly, and this is no exception.  Make both of the uncallable
methods go away.

BUG=501889
R=thestig@chromium.org

Review URL: https://codereview.chromium.org/1179773007.
1 file changed