Pull in specific revision of PDF corpus via DEPS.

Pull in specific revision of PDF corpus via DEPS.

There are two reasons for doing this. The first is that adding files
to this repository doesn't trigger a rebuild on the bot, so the next
unrelated pdfium change will be the one to hit any issues with the
unversioned corpus.

The second is that we may need a specific version of the expected output
files (.pngs) to go with a specific pdfium build.

R=thestig@chromium.org

Committed: https://pdfium.googlesource.com/pdfium/+/76a61ca39a235dbe4c5df5fca93e1cfff8879113

[Tom Sepez, 2015-03-19 21:16:52]

tsepez@chromium.org changed reviewers:
+ thestig@chromium.org

[Tom Sepez, 2015-03-19 21:16:52]

Lei, please review (mainly the CL description).

[Lei Zhang, 2015-03-19 21:25:49]

lgtm

[Tom Sepez, 2015-03-19 21:35:28]

Committed patchset #1 (id:1) manually as
76a61ca39a235dbe4c5df5fca93e1cfff8879113 (presubmit successful).