Roll src/third_party/pdfium/ a0af75cc4..d9dfb6cc1 (3 commits)

https://pdfium.googlesource.com/pdfium.git/+log/a0af75cc4d1e..d9dfb6cc16f6

$ git log a0af75cc4..d9dfb6cc1 --date=short --no-merges --format='%ad %ae %s'
2018-01-04 dsinclair Merge CXFA_WidgetData into CXFA_WidgetAcc
2018-01-04 dsinclair Make CXFA_WidgetData constructor protected
2018-01-04 dsinclair Remove CXFA_DataData

Created with:
  roll-dep src/third_party/pdfium


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

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.


TBR=dsinclair@chromium.org

Change-Id: Iedbc18180871bb5a017ae32e183e4e86eb266da3
Reviewed-on: https://chromium-review.googlesource.com/850948
Reviewed-by: <pdfium-deps-roller@chromium.org>
Commit-Queue: <pdfium-deps-roller@chromium.org>
Cr-Commit-Position: refs/heads/master@{#527061}

DEPS

@@ -102,7 +102,7 @@ vars = {
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling PDFium
   # and whatever else without interference from each other.
-  'pdfium_revision': 'a0af75cc4d1e50bb2832dc58636043afe565b02b',
+  'pdfium_revision': 'd9dfb6cc16f689753e9b3f896fbda1aec791051a',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling openmax_dl
   # and whatever else without interference from each other.