Roll src/third_party/pdfium/ 2d510f7dc..c2db74bb6 (2 commits)

https://pdfium.googlesource.com/pdfium.git/+log/2d510f7dc4d6..c2db74bb65ab

$ git log 2d510f7dc..c2db74bb6 --date=short --no-merges --format='%ad %ae %s'
2017-09-19 thestig Default to c++11 instead of c++14.
2017-09-19 dsinclair Setting focus on a widget may destroy the widget

Created with:
  roll-dep src/third_party/pdfium


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: I57db7330aa7d221aa3a5e9e336d90fe76be8d8dd
Reviewed-on: https://chromium-review.googlesource.com/673131
Reviewed-by: <pdfium-deps-roller@chromium.org>
Commit-Queue: <pdfium-deps-roller@chromium.org>
Cr-Commit-Position: refs/heads/master@{#502940}

DEPS

@@ -65,7 +65,7 @@ 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': '2d510f7dc4d6c30cdecef09c5e68c47e98de6ffb',
+  'pdfium_revision': 'c2db74bb65ab320b9c8da4fc3bee03d9d3f14943',
   # 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.