GitLab

Split raster PDF creation into its own function. Also add a helper
function to consistently check for PDFs with no pages.

Change-Id: I693282460b4da0e80bd1c5f2c022372bb7d58bb1
Reviewed-on: https://chromium-review.googlesource.com/1238353
Commit-Queue: Lei Zhang <thestig@chromium.org>
Reviewed-by: Rebekah Potter <rbpotter@chromium.org>
Cr-Commit-Position: refs/heads/master@{#593623}