Roll src/third_party/pdfium 50710e758168..d1fb2c5fcaa3 (2 commits)

https://pdfium.googlesource.com/pdfium.git/+log/50710e758168..d1fb2c5fcaa3


git log 50710e758168..d1fb2c5fcaa3 --date=short --no-merges --format='%ad %ae %s'
2019-06-24 asweintraub@google.com Fix overloaded operators in bigint.
2019-06-24 asweintraub@google.com Fix assignment operator return values in agg.


Created with:
  gclient setdep -r src/third_party/pdfium@d1fb2c5fcaa3

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.


TBR=pdfium-deps-rolls@chromium.org

Change-Id: I6d24bb032c33f8856f012f99b9f709ce0238232f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1671903Reviewed-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@{#671933}

DEPS

@@ -158,7 +158,7 @@ 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': '50710e758168bc5a6288251aa25237a267c5ed15',
+  'pdfium_revision': 'd1fb2c5fcaa3c381b519651df72ef08b64bc2e87',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling BoringSSL
   # and whatever else without interference from each other.