Roll src/third_party/pdfium/ b4fee4d5d..d1a8458e6 (7 commits)

https://pdfium.googlesource.com/pdfium.git/+log/b4fee4d5d471..d1a8458e6390

$ git log b4fee4d5d..d1a8458e6 --date=short --no-merges --format='%ad %ae %s'
2017-08-02 thestig Avoid a redundant header offset check in CPDF_Parser.
2017-08-02 hnakashima Replace CFX_ByteTextBuf with ostringstream in cfx_psrenderer.cpp.
2017-08-02 hnakashima Replace CFX_ByteTextBuf from cpdf_security_handler.cpp with std::vector
2017-08-02 rharrison Remove unused FromUnicode method
2017-08-02 art-snake Unify parsing of cross refs v4
2017-08-02 rharrison Remove parameter from GetID
2017-08-02 rharrison Remove support for out of bounds params in Delete

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: I633fc2cb7101cc1fcb0f8dc57be00c8f54f3c55c
Reviewed-on: https://chromium-review.googlesource.com/599392
Reviewed-by: <pdfium-deps-roller@chromium.org>
Commit-Queue: <pdfium-deps-roller@chromium.org>
Cr-Commit-Position: refs/heads/master@{#491661}

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': 'b4fee4d5d471475ada1d0d9110e1a534b49477ba',
+  'pdfium_revision': 'd1a8458e6390103e123e9d265040b3d02c16955b',
   # 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.