Roll src/third_party/pdfium/ 5f34d479d..5171a27ea (1 commit)

https://pdfium.googlesource.com/pdfium.git/+log/5f34d479d06e..5171a27eaa74

$ git log 5f34d479d..5171a27ea --date=short --no-merges --format='%ad %ae %s'
2017-06-01 tsepez Use unique_ptrs for codec contexts in ccodec_progressivedecoder.

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: I927f171f64bba1e6b989db6a09e4bb859bc036ce
Reviewed-on: https://chromium-review.googlesource.com/521766
Reviewed-by: <pdfium-deps-roller@chromium.org>
Commit-Queue: <pdfium-deps-roller@chromium.org>
Cr-Commit-Position: refs/heads/master@{#476468}

DEPS

@@ -64,7 +64,7 @@ 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': '5f34d479d06ebab9079c2d0704dee872cc45dd86',
+  'pdfium_revision': '5171a27eaa7489939310bd2864864867cc78ce21',
   # 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.