Roll src/third_party/pdfium 6c23cd33e6fe..8607c59b3c65 (7 commits)

https://pdfium.googlesource.com/pdfium.git/+log/6c23cd33e6fe..8607c59b3c65

git log 6c23cd33e6fe..8607c59b3c65 --date=short --first-parent --format='%ad %ae %s'
2020-02-07 nigi@chromium.org Roll third_party/depot_tools/ e9730d75a..816c2b354 (46 commits; 8 trivial rolls)
2020-02-06 tsepez@chromium.org Move JS helper testIllegalConstructor() to its own .js file.
2020-02-06 tsepez@chromium.org Remove class_name argument from JSSpecialProp methods
2020-02-06 tsepez@chromium.org Remove templates from JSSpecialProp methods.
2020-02-06 tsepez@chromium.org Add tests for XFA's JS global object.
2020-02-06 thestig@chromium.org Roll third_party/skia/ d50cc9587..81d35a72a (1037 commits; 204 trivial rolls)
2020-02-06 tsepez@chromium.org Test removing last instanceManager instance.

Created with:
  gclient setdep -r src/third_party/pdfium@8607c59b3c65

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: Ibd69828808601fc97be71cec009961d124a6c7ff
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2042549Reviewed-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@{#739295}

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': '6c23cd33e6fe27335f7ac6c83b87ffdf9184593e',
+  'pdfium_revision': '8607c59b3c65d3cb99924ce6e22968bafa20e61f',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling BoringSSL
   # and whatever else without interference from each other.