Roll PDFium from fe8e758b920c to b70f99dcd334 (7 revisions)

https://pdfium.googlesource.com/pdfium.git/+log/fe8e758b920c..b70f99dcd334

2020-08-08 zhouhan@google.com Add support for action /GoToE
2020-08-08 tsepez@chromium.org Split off CFXJSE_Engine::GetScriptObject() from GetThisObject().
2020-08-08 tsepez@chromium.org Track CJX_Objects in CFXJSE_Engine::m_mapVariableToContext.
2020-08-07 tsepez@chromium.org Track CJX_Objects in CFXJSE_Engine::m_mapObjectToValue
2020-08-06 tsepez@chromium.org Remove CFXJSE_Engine::RemoveJSBindingFromMap()
2020-08-06 tsepez@chromium.org Provide better layering for FWL theme providers.
2020-08-06 thestig@chromium.org Sync skia/BUILD.gn with Chromium's copy.

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: I2388d414b73b9d80d59111168064d17f5b1cdf4c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2343741Reviewed-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@{#796207}

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': 'fe8e758b920cfac78a21f518b3797fdb368ef958',
+  'pdfium_revision': 'b70f99dcd33477cd588e7758fa5c2af345a172f8',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling BoringSSL
   # and whatever else without interference from each other.