Roll PDFium from 7257a3f99111 to 2b2e1584ef6d (8 revisions)

https://pdfium.googlesource.com/pdfium.git/+log/7257a3f99111..2b2e1584ef6d

2020-09-18 thestig@chromium.org Add a test case for FPDFText_GetCharBox() returning tall char box.
2020-09-18 thestig@chromium.org Mark some CFX_DIBitmap methods as Skia-only.
2020-09-18 thestig@chromium.org Make char widths signed again.
2020-09-18 thestig@chromium.org Add a test case for Type3 glyphs with negative width.
2020-09-18 tsepez@chromium.org Garbage collect CXFA_CalcData.
2020-09-18 tsepez@chromium.org Avoid duplicate CFGAS_GEModule creation in pdf_bidi_fuzzer.
2020-09-18 thestig@chromium.org Mark RenderDeviceDriverIface::SetBitsWithMask() as Skia-only.
2020-09-18 thestig@chromium.org Remove RenderDeviceDriverIface::StartRendering() and EndRendering().

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,thestig@google.com 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:1128284,chromium:1129720,chromium:806612
Tbr: pdfium-deps-rolls@chromium.org,thestig@google.com
Change-Id: Ib40d82e6032fc107c9c0476f3a08f8d4e3b6eb91
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2419637Reviewed-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@{#808654}

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': '7257a3f99111c6376d659b0b554a0a93f5f63495',
+  'pdfium_revision': '2b2e1584ef6ddc352d829848a1433cdd036e965e',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling BoringSSL
   # and whatever else without interference from each other.