Roll PDFium

A newer version of PDFium is needed to unblock GN work.

Sheriffs: Revert first and ask questions later.
The last time this rolled, the build broke due to an issue that can
not be caught by the current trybots/CQ configuration.  I've applied
a speculative fix based upon the compilation logs for that run,
but can't be 100%.

This pulls in:
d1f792a Fix subtle issues in opj_skip_from_memory and add unit tests.
74b81d9 Revert "TEST that the tree goes RED when pixel/javascript tests fail." This reverts commit de00893874a9d5ecae497e00511e2395fc2f02e8.
de00893 TEST that the tree goes RED when pixel/javascript tests fail.
2c4f5ea Return OS status code from python test driver scripts.
a416173 Revert "Fix a problem that JP2 image is not displayed because index color space is used"
b29e12a Pull our new test case repository via deps.
a7865e9 Speculative fix for breakage in pdfum DEPS roll
5a0e504 Fix a problem that JP2 image is not displayed because index color space is used
cd3c476 Fix a bug that JPX images can't be shown
ae5b85a Fix potential integer overflow in fpdf_render_image.cpp
b8cd18a Revert "Kill CFX_GrowOnlyPool."
090d683 Kill CFX_GrowOnlyPool.
3c676ec Kill remaining sprintfs
1e580a1 Fix multiply defined macro in zlib.h on linux_chromium_clobber_rel_ng builder.
0700106 Make conversions for CPDF_Link explicit.
8842c62 Fix the pdfium component build.
5a370d7 Make conversion between CPDF_Dest and its object explicit.
7348fae Add gmock to .gitignore
624b6c1 Make conversion between CPDF_Action and its dictionary explicit.
61c25ee Merge to Master: Fix a compiling error in fxjs_v8.h
e1671bd Kill off JS_ErrorString type.
b720d0a Return error information from pdfium to JS.
944ccad Do hit tests against Annots in reverse order.
5b47dbf Remove unused IDS_ constants from pdfium.
3d25502 Pull in gmock for standalone pdfium builds.
ec61a85 Upgrade openjpeg to revision 2997.
42a8ada Implement a delegate for EmbedderTests.
57e4c86 Kill off unused IFXJS interface methods.
4351ac2 Fix compilation error on Windows.
f9cfdda Add small flate decode unit test.
e796478 Kill multi-byte comments in fxet_list.h
23f9288 Convert pdfium expected test results to PNG format.
0fd53cf Fix GN build after PNG support backport
ef1e85c Backport PNG output format to origin/master branch.

Review URL: https://codereview.chromium.org/1024703002

Cr-Commit-Position: refs/heads/master@{#321618}

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': '28ddd48bfd84c55cc51d0b16fa533c51affdeb5b',
+  'pdfium_revision': 'ae702b094ba8fda303b4c7e6ddafb3ebae6db7b6',
   # 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.