This script populates doc/generated. This directory is named in
.gitignore on the master branch, but will not be ignored on the doc
branch. The plan is to merge master into doc and run this script to
generate and check in a new set of generated docs.
BUG=crashpad:67
R=rsesek@chromium.org
Review URL: https://codereview.chromium.org/1397683003 .
