Roll src/third_party/pdfium/ 21ce1a68b..4d9df422c (1 commit).

DEPS

 # This file is used to manage the dependencies of the Chromium src repo. It is
 # used by gclient to determine what version of each dependency to check out, and
 # where.
 #
 # For more information, please refer to the official documentation:
 #   https://sites.google.com/a/chromium.org/dev/developers/how-tos/get-the-code
 #
 # When adding a new dependency, please update the top-level .gitignore file
 # to list the dependency's destination directory.
 #
@@ skipping 42 matching lines @@
   # the commit queue can handle CLs rolling build tools
   # and whatever else without interference from each other.
   'buildtools_revision': 'adb8bf4e8fc92aa1717bf151b862d58e6f27c4f2',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling SwiftShader
   # and whatever else without interference from each other.
   'swiftshader_revision': '3e204de9bb74b5379b42b7eea5c4b898b2698d56',
   # 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': '21ce1a68bb9f80bfbd4f295fd3b7181e56502fdc',
+  'pdfium_revision': '4d9df422c340b3bc33e044d3d94e1ff9582e1260',
   # 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.
   'openmax_dl_revision': '57d33bee7823e76393692f8d58e0478d6b79d153',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling BoringSSL
   # and whatever else without interference from each other.
   'boringssl_revision': '07e7806177c92dede456874e74d4c92d8dc224b2',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling google-toolbox-for-mac
@@ skipping 946 matching lines @@
                 "--no_auth",
                 "-u",
                 "--bucket", "v8-wasm-asmjs-fuzzer",
                 "-s", "src/v8/test/fuzzer/wasm_asmjs.tar.gz.sha1",
     ],
   },
 ]
 
 # ANGLE manages DEPS that it also owns the build files for, such as dEQP.
 recursedeps = [("src/third_party/angle", "DEPS.chromium")]