Roll src/third_party/pdfium e020cf38f429..addc9bfc6cd1 (7 commits)

https://pdfium.googlesource.com/pdfium.git/+log/e020cf38f429..addc9bfc6cd1

git log e020cf38f429..addc9bfc6cd1 --date=short --first-parent --format='%ad %ae %s'
2019-12-19 thestig@chromium.org Expose MakeTag() as CFX_FontMapper::MakeTag().
2019-12-19 thestig@chromium.org Switch testing/image_diff/ code to use uint8_t instead of unsigned char.
2019-12-19 thestig@chromium.org Add core/fxcrt/byteorder.h.
2019-12-19 thestig@chromium.org Do less work in XFATestEnvironment::SetUp().
2019-12-19 thestig@chromium.org Remove some references to fxcrt namespace.
2019-12-19 thestig@chromium.org Avoid using std::function to improve performance.
2019-12-19 nigi@chromium.org Remove parsing decimal numbers in StringToCode().

Created with:
  gclient setdep -r src/third_party/pdfium@addc9bfc6cd1

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: I7b4b7ff062b46de17934f76ac304d66a44d4355e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1976661Reviewed-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@{#726495}

DEPS

@@ -195,7 +195,7 @@ 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': 'e020cf38f4293198c6fbdea9742b0b0e9f74b558',
+  'pdfium_revision': 'addc9bfc6cd13c0ba8f3d10ecbd7c9b6102ae4a2',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling BoringSSL
   # and whatever else without interference from each other.