Roll src/third_party/pdfium/ 8384757b2..df673c281 (2 commits)

https://pdfium.googlesource.com/pdfium.git/+log/8384757b2b00..df673c28191c

$ git log 8384757b2..df673c281 --date=short --no-merges --format='%ad %ae %s'
2017-05-04 dsinclair Cleanup more null IFX_Pause parameters
2017-05-04 dsinclair Remove some unused IFX_Pause params

Created with:
  roll-dep src/third_party/pdfium


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

Change-Id: I6195944d1434725871e800f62e1097275e84f5f7
Reviewed-on: https://chromium-review.googlesource.com/495411
Reviewed-by: <pdfium-deps-roller@chromium.org>
Commit-Queue: <pdfium-deps-roller@chromium.org>
Cr-Commit-Position: refs/heads/master@{#469376}

DEPS

@@ -64,7 +64,7 @@ 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': '8384757b2b00f11971d588f6fbe3a8c9aa755151',
+  'pdfium_revision': 'df673c28191cca181ef526d02f24b4a7a6f5e200',
   # 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.