Roll src/third_party/pdfium f5ad5c1a3f33..c2da3ad9993b (3 commits)

https://pdfium.googlesource.com/pdfium.git/+log/f5ad5c1a3f33..c2da3ad9993b

git log f5ad5c1a3f33..c2da3ad9993b --date=short --no-merges --format='%ad %ae %s'
2019-09-14 awscreen@chromium.org [FXCRT] Add string<->double support routines
2019-09-13 thestig@chromium.org Fix variable name mismatches in CPDF_Array.
2019-09-13 awscreen@chromium.org [FXCRT] Add double rounding support

Created with:
  gclient setdep -r src/third_party/pdfium@c2da3ad9993b

If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://autoroll.skia.org/r/pdfium-autoroll
Please CC pdfium-deps-rolls@chromium.org on the revert to ensure that a human
is aware of the problem.

To report a problem with the AutoRoller itself, please file a bug:
https://bugs.chromium.org/p/skia/issues/entry?template=Autoroller+Bug

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

TBR=pdfium-deps-rolls@chromium.org

Bug: chromium:611744,chromium:611744
Change-Id: I14639c7499833e6a9b620b54ffda9a339e75c4e5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1804814Reviewed-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@{#696632}

DEPS

@@ -182,7 +182,7 @@ 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': 'f5ad5c1a3f33358cd8cb05f60e80fb076365d749',
+  'pdfium_revision': 'c2da3ad9993bb1611691a18032a12306d0e378b3',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling BoringSSL
   # and whatever else without interference from each other.