Add pdf_date_fuzzer for chrome_pdf::ParsePdfDate()

Bug: 93619
Change-Id: I14ffeabbbfac3321167f735329c0b7b50a2709f0
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2617131
Commit-Queue: Daniel Hosseinian <dhoss@chromium.org>
Reviewed-by: Tom Sepez <tsepez@chromium.org>
Cr-Commit-Position: refs/heads/master@{#843357}

pdf/BUILD.gn

@@ -5,6 +5,7 @@
 import("//build/buildflag_header.gni")
 import("//build/config/features.gni")
 import("//pdf/features.gni")
+import("//testing/libfuzzer/fuzzer_test.gni")
 import("//testing/test.gni")
 import("//third_party/pdfium/pdfium.gni")
 import("//v8/gni/v8.gni")
@@ -377,6 +378,15 @@ if (enable_pdf) {
       data += [ "$root_out_dir/snapshot_blob.bin" ]
     }
   }
+
+  fuzzer_test("pdf_dates_fuzzer") {
+    sources = [ "pdf_utils/dates_fuzzer.cc" ]
+
+    deps = [
+      ":internal",
+      "//base",
+    ]
+  }
 } else {
   # Dummy groups when PDF support is disabled so targets can unconditionally
   # depend on it.

pdf/pdf_utils/dates_fuzzer.cc

@@ -0,0 +1,17 @@
+// Copyright 2021 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include <stddef.h>
+#include <stdint.h>
+
+#include <string>
+
+#include "base/time/time.h"
+#include "pdf/pdf_utils/dates.h"
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
+  const std::string input(reinterpret_cast<const char*>(data), size);
+  chrome_pdf::ParsePdfDate(input);
+  return 0;
+}