Roll src/third_party/pdfium 4a0f1a01ac8a..d9bd62fafb66 (4 commits)

https://pdfium.googlesource.com/pdfium.git/+log/4a0f1a01ac8a..d9bd62fafb66

git log 4a0f1a01ac8a..d9bd62fafb66 --date=short --first-parent --format='%ad %ae %s'
2020-02-12 tsepez@chromium.org Deduplicate a switch statement in cpdfsdk_appstream.cpp.
2020-02-12 tsepez@chromium.org Remove some unused methods and members from CFX_CSSSyntaxParser.
2020-02-11 tsepez@chromium.org Provide test for CJX_Packet methods from JavaScript.
2020-02-11 thestig@chromium.org Add a test case for a FPDFText_GetLooseCharBox() bug.

Created with:
  gclient setdep -r src/third_party/pdfium@d9bd62fafb66

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

Bug: None
Tbr: pdfium-deps-rolls@chromium.org
Change-Id: Id4da242671888f96d565c8c0d4c5f11203a2630c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2050452Reviewed-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@{#740517}

DEPS

@@ -191,7 +191,7 @@ 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': '4a0f1a01ac8a9214c791e99baaf2ddbe914629da',
+  'pdfium_revision': 'd9bd62fafb662f5dce8bf36bb61d4d0e5b263496',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling BoringSSL
   # and whatever else without interference from each other.