Roll PDFium from 1877f680e3b2 to 1e7df19a137f (6 revisions)

https://pdfium.googlesource.com/pdfium.git/+log/1877f680e3b2..1e7df19a137f

2020-09-04 thestig@chromium.org Revert "Optimize a tight loop in FX_Number."
2020-09-04 tsepez@chromium.org Remove CFGAS_FontMgr::EnumFontFromFiles.
2020-09-03 nigi@chromium.org Enable FPDFFlattenEmbedderTest.BUG_889099 for Skia/SkiaPaths.
2020-09-03 tsepez@chromium.org Fix some layering between fpdfsdk and fxbarcode.
2020-09-03 tsepez@chromium.org Initialize CPPGC heap with kNoConservativeStack.
2020-09-03 tsepez@chromium.org Tidy CFX_Font

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: chromium:1124998
Tbr: pdfium-deps-rolls@chromium.org
Change-Id: Icad9dc4826d872eb2bdb59afd73b9773d240e005
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2393386Reviewed-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@{#804529}

DEPS

@@ -215,7 +215,7 @@ 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': '1877f680e3b229bf5b3807f86208921d10128a13',
+  'pdfium_revision': '1e7df19a137f290064bc098e9ccbf82232197285',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling BoringSSL
   # and whatever else without interference from each other.