Roll src/third_party/pdfium/ 156de0259..cae6bdfff (1 commit).

https://pdfium.googlesource.com/pdfium.git/+log/156de02596e9..cae6bdfff7e4

$ git log 156de0259..cae6bdfff --date=short --no-merges --format='%ad %ae %s'
2016-08-25 jaepark Remove unused IPDFSDK_AnnotHandler::GetName().

TBR=dsinclair@chromium.org

Review-Url: https://codereview.chromium.org/2278163002
Cr-Commit-Position: refs/heads/master@{#414448}

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': '156de02596e91490bf2432686d0d3c91a5c1a26e',
+  'pdfium_revision': 'cae6bdfff7e409312f2f88548be5b30abfa84147',
   # 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.