Roll src/third_party/pdfium/ 4ce4f5f8a..480ca10f7 (12 commits)

https://pdfium.googlesource.com/pdfium.git/+log/4ce4f5f8ab0b..480ca10f7a20

$ git log 4ce4f5f8a..480ca10f7 --date=short --no-merges --format='%ad %ae %s'
2017-10-05 dsinclair Remove unused CPVT_SecProps
2017-10-05 dsinclair Remove more unused params
2017-10-05 dsinclair Remove unused parameters
2017-10-05 rharrison Add ObservedPtr to catch Widget being killed by JS
2017-10-05 rharrison Add ObservedPtrs to catch issues in SaveData
2017-10-05 npm Create FreeType roll script
2017-10-04 rharrison Make GIF decoder more standards complaint
2017-10-05 dsinclair Move CPDF_RenderOptions members to private
2017-10-05 dsinclair Remove friend from CPDF_ApSettings
2017-10-05 npm Roll FT to ae7dc1f62d826083d418e86cce3f66a76dff038a
2017-10-05 dsinclair Remove friends from form code
2017-10-05 dsinclair Remove friends from CPDF_VariableText

Created with:
  roll-dep src/third_party/pdfium
BUG=771979,756427,770337


Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+/master/autoroll/README.md

If the roll is causing failures, see:
http://www.chromium.org/developers/tree-sheriffs/sheriff-details-chromium#TOC-Failures-due-to-DEPS-rolls


TBR=dsinclair@chromium.org

Change-Id: I875e810e00b7d619534e2dc24519c27088423e15
Reviewed-on: https://chromium-review.googlesource.com/703198
Reviewed-by: <pdfium-deps-roller@chromium.org>
Commit-Queue: <pdfium-deps-roller@chromium.org>
Cr-Commit-Position: refs/heads/master@{#506857}

DEPS

@@ -69,7 +69,7 @@ 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': '4ce4f5f8ab0b25ac10a5c66cac1a8c281e24a69b',
+  'pdfium_revision': '480ca10f7a20dd65921dcec046d91b503f3599c3',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling openmax_dl
   # and whatever else without interference from each other.