Roll src/third_party/pdfium/ 2ca2da505..89f8fa869 (1 commit).

https://pdfium.googlesource.com/pdfium.git/+log/2ca2da505ba7..89f8fa8694bb

$ git log 2ca2da505..89f8fa869 --date=short --no-merges --format='%ad %ae %s'
2016-09-14 dsinclair Remove unused code in CPDFXFA_Document

TBR=dsinclair@chromium.org

Review-Url: https://codereview.chromium.org/2338243002
Cr-Commit-Position: refs/heads/master@{#418559}

DEPS

@@ -60,7 +60,7 @@ 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': '2ca2da505ba75cd830539ffc98dfc482fd4daa41',
+  'pdfium_revision': '89f8fa8694bbf209412845c250af48bbc539962b',
   # 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.