Roll src/third_party/pdfium c3099d1c6942..174de19776de (2 commits)

https://pdfium.googlesource.com/pdfium.git/+log/c3099d1c6942..174de19776de


git log c3099d1c6942..174de19776de --date=short --no-merges --format='%ad %ae %s'
2018-09-19 thestig@chromium.org Encapsulate CPDF_ImageLoader.
2018-09-19 thestig@chromium.org Validate decoder pipelines.


Created with:
  gclient setdep -r src/third_party/pdfium@174de19776de

The AutoRoll server is located here: https://autoroll.skia.org/r/pdfium-autoroll

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+/master/autoroll/README.md

If the roll is causing failures, please contact the current sheriff, who should
be CC'd on the roll, and stop the roller if necessary.



BUG=chromium:880675
TBR=dsinclair@chromium.org

Change-Id: I1af59ee6d0a3d3c21cce116d96083947b365ee31
Reviewed-on: https://chromium-review.googlesource.com/1234295
Reviewed-by: chromium-autoroll <chromium-autoroll@skia-public.iam.gserviceaccount.com>
Commit-Queue: chromium-autoroll <chromium-autoroll@skia-public.iam.gserviceaccount.com>
Cr-Commit-Position: refs/heads/master@{#592495}