Roll PDFium

Roll PDFium

This brings in:

28ddd48  Replace second set of #defines with templates in JS_Define.h
94dd28e  Update GN build files w/ cpu_arch -> current_cpu changes.
dce5730  Add test for PDF's JS "global".
a96cc9b  Replace ugly JS_Define macros with templates.
2da7bd4  Tidy up JS_Defines.h
7435e8e  Run pixel tests via automated script.
83c87e5  run_javascript_tests.py: Be more flexible about directory layout.

TBR=jam@chromium.org, tsepez@chromium.org
BUG=344767
Committed: https://crrev.com/a2592d89e85232a83f905b679d273444f60b760a
Cr-Commit-Position: refs/heads/master@{#317684}

[Dirk Pranke, 2015-02-23 22:55:42]

The CQ bit was checked by dpranke@chromium.org

[commit-bot: I haz the power, 2015-02-23 22:56:29]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/948933003/1

[Tom Sepez, 2015-02-23 23:00:13]

lgtm

[jam, 2015-02-23 23:55:30]

lgtm

[commit-bot: I haz the power, 2015-02-24 00:12:32]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-02-24 00:13:06]

Patchset 1 (id:??) landed as
https://crrev.com/a2592d89e85232a83f905b679d273444f60b760a
Cr-Commit-Position: refs/heads/master@{#317684}