Roll src/third_party/pdfium 7f446cc3c798..dacaac7b0f29 (4 commits)

https://pdfium.googlesource.com/pdfium.git/+log/7f446cc3c798..dacaac7b0f29

git log 7f446cc3c798..dacaac7b0f29 --date=short --first-parent --format='%ad %ae %s'
2020-04-23 bravi@microsoft.com Implemented URI Action Handling for links
2020-04-23 thestig@chromium.org Fix nits in StructElement code.
2020-04-23 thestig@chromium.org Do IWYU to fix building with gcc.
2020-04-23 thestig@chromium.org Auto format GN build files.

Created with:
  gclient setdep -r src/third_party/pdfium@dacaac7b0f29

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: chromium:994500
Tbr: pdfium-deps-rolls@chromium.org
Change-Id: I860977fb5ed2a5b74398b98891480677f9ccd865
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2163457Reviewed-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@{#762088}

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': '7f446cc3c79882af7860771d4a54c536cc75b74b',
+  'pdfium_revision': 'dacaac7b0f299e09b9072710a4f2924102621b9b',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling BoringSSL
   # and whatever else without interference from each other.