Port https://codereview.chromium.org/398163006 to gn.
Port https://codereview.chromium.org/398163006 to gn.

BUG=376399
TBR=thestig

Review URL: https://codereview.chromium.org/1415883010 .

andoma/pdfium,DrAlexx/pdfium,DrAlexx/pdfium,DrAlexx/pdfium,andoma/pdfium,DrAlexx/pdfium,andoma/pdfium,andoma/pdfium