Roll PDFium from 1c8311278ae8 to a15da341200e (4 revisions)

https://pdfium.googlesource.com/pdfium.git/+log/1c8311278ae8..a15da341200e

2020-11-14 tsepez@chromium.org Split up CFXJSE_FormCalcContext::ApplyToExpansion()
2020-11-14 tsepez@chromium.org Consolidate some common logic in cfxjse_formcalccontext.cpp.
2020-11-13 dhoss@chromium.org Purge every C-style cast of int32_t
2020-11-13 tsepez@chromium.org Add one-pager examples for PDFium initialization.

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/+doc/master/autoroll/README.md

Bug: None
Tbr: pdfium-deps-rolls@chromium.org
Change-Id: I7e1ca0f85a39f74b05e3f0baf85e8380460bbf7b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2538736Reviewed-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@{#827592}

DEPS

@@ -217,7 +217,7 @@ 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': '1c8311278ae8bfbb4b4f86895899cabf48f67542',
+  'pdfium_revision': 'a15da341200e10f12262331da42fc81b3c4389ef',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling BoringSSL
   # and whatever else without interference from each other.