Roll PDFium.

This brings in:

b3a788e  Fix GN PDFium build when building all.
f8af677  Always use the FreeType headers included in PDFium.
7dc63e6  Fix heap buffer overflow in CPDF_SampledFunc::v_Call
dc8c950  Don't export any OpenJPEG methods from PDFium.
71c24b8  Use system FreeType on Linux.
b38a900  Track formhandles in EmbedderTest class itself
14b2bb0  Fix infinite recursion in CPDF_RenderStatus::RenderSingleObject().
1d43e82  Add minimized test cases for stack exhaustion crash to repository.
cedc562  Merge to Master: Add output scale factor command line parameter to pdfium_test.
90f9e61  Merge to Master: Cover fpdftext.h API with embeddertests.
506e6dc  Add embedder test for stream length beyond end of file.

TBR=tsepez

Review URL: https://codereview.chromium.org/883913003

Cr-Commit-Position: refs/heads/master@{#314099}

DEPS

@@ -66,7 +66,7 @@ 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': 'eef005055d6aafc2cc6066af37ce47d8b15ec7cd',
+  'pdfium_revision': 'b3a788e5e37955620b26be5b6e3048d37b605e00',
   # 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.