Change XFA fuzzer to use new API for detecting XFA forms

Includes a manual roll of PDFium in DEPS to 
854d71c1420eb80ec79755a6cdf829f3f39aead7, to pick up the new API.

BUG=chromium:775615

Change-Id: I186a7f385eb50c59718dabc1407d49564cf3547a
Reviewed-on: https://chromium-review.googlesource.com/724021
Reviewed-by: dsinclair <dsinclair@chromium.org>
Commit-Queue: Ryan Harrison <rharrison@chromium.org>
Cr-Commit-Position: refs/heads/master@{#509839}

DEPS

@@ -79,7 +79,7 @@ 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': '7c2daec0a5f5d5e0f442db7946e9356daa7c55b2',
+  'pdfium_revision': '854d71c1420eb80ec79755a6cdf829f3f39aead7',
   # 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.

pdf/pdfium/fuzzers/pdfium_xfa_fuzzer.cc

@@ -4,12 +4,6 @@
 
 #include "pdf/pdfium/fuzzers/pdfium_fuzzer_helper.h"
 
-// TODO(mmoroz,rharrison): remove this after landing of
-// https://chromium-review.googlesource.com/c/chromium/src/+/724021
-#ifndef DOCTYPE_PDF
-#define DOCTYPE_PDF 0
-#endif
-
 class PDFiumXFAFuzzer : public PDFiumFuzzerHelper {
  public:
   PDFiumXFAFuzzer() : PDFiumFuzzerHelper() {}
@@ -20,8 +14,8 @@ class PDFiumXFAFuzzer : public PDFiumFuzzerHelper {
   // Return false if XFA doesn't load as otherwise we're duplicating the work
   // done by the non-xfa fuzzer.
   bool OnFormFillEnvLoaded(FPDF_DOCUMENT doc) override {
-    int doc_type = DOCTYPE_PDF;
-    if (!FPDF_HasXFAField(doc, &doc_type) || doc_type == DOCTYPE_PDF)
+    int form_type = FPDF_GetFormType(doc);
+    if (form_type != FORMTYPE_XFA_FULL && form_type != FORMTYPE_XFA_FOREGROUND)
       return false;
     return FPDF_LoadXFA(doc);
   }