roll pdfium to 2d28224

Includes:

2d28224 Fix a bug when assign the generation number of indirect objects
26019d4 Adjust the order of clearing resource in CPDF_DocPageData::Clear

TBR=tsepez@chromium.org
BUG=416155

Review URL: https://codereview.chromium.org/584023007

Cr-Commit-Position: refs/heads/master@{#295864}

DEPS

@@ -59,7 +59,7 @@ 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': 'e0399c76ba1412926a3d55f6328a095c23467951',
+  'pdfium_revision': '2d282243dbd1edd51d42e13f563903a1a76ce8f8',
   # 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.