Roll src/third_party/pdfium/ 8fa82794f..96f482c9c (2 commits).

https://pdfium.googlesource.com/pdfium.git/+log/8fa82794ffc2..96f482c9cd3c

$ git log 8fa82794f..96f482c9c --date=short --no-merges --format='%ad %ae %s'
2017-01-11 dsinclair Convert FDE CSS enums to enum classes.
2017-01-11 npm Really fix m_nb_mct_records calculation in opj_j2k_read_mct

BUG=678461,680102

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

If the roll is causing failures, see:
http://www.chromium.org/developers/tree-sheriffs/sheriff-details-chromium#TOC-Failures-due-to-DEPS-rolls

TBR=dsinclair@chromium.org

Review-Url: https://codereview.chromium.org/2623103004
Cr-Commit-Position: refs/heads/master@{#443057}