Roll src/third_party/pdfium/ cde5101eb..e9988dd65 (1 commit).

https://pdfium.googlesource.com/pdfium.git/+log/cde5101eb15b..e9988dd65e74

$ git log cde5101eb..e9988dd65 --date=short --no-merges --format='%ad %ae %s'
2016-09-16 npm Reduce duplicated code in CPDF_Document by adding auxiliary methods

TBR=dsinclair@chromium.org

Review-Url: https://codereview.chromium.org/2345933003
Cr-Commit-Position: refs/heads/master@{#419293}

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': 'cde5101eb15b24519e89fa500fe37038bc8e2201',
+  'pdfium_revision': 'e9988dd65e743a9b70482aa3007cec2c9789f679',
   # 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.