Add support for building with goma.

Add support for building with goma.

R=thakis@chromium.org, thestig@chromium.org

Committed: https://pdfium.googlesource.com/pdfium/+/e35b445bee90390ea09f334cbff4a6220537bbda

[Oliver Chang, 2015-11-03 20:58:07]

Description was changed from

==========
Add support for building with goma.

BUG=
==========

to

==========
Add support for building with goma.

R=thakis@chromium.org,thestig@chromium.org
==========

[Oliver Chang, 2015-11-03 20:58:07]

ochang@chromium.org changed reviewers:
+ thakis@chromium.org, thestig@chromium.org

[Oliver Chang, 2015-11-03 20:58:21]

ptal

[Nico, 2015-11-03 21:01:12]

lgtm

(do you have any with / without goma build numbers? pdfium is fairly small,
maybe it doesn't help all that much here…)

[Lei Zhang, 2015-11-03 21:05:45]

On 2015/11/03 21:01:12, Nico wrote:
> lgtm
> 
> (do you have any with / without goma build numbers? pdfium is fairly small,
> maybe it doesn't help all that much here…)

It helps, more on computers with only 6 cores. I've been running it locally (and
with clang) via manually setting CC/CXX.

[Oliver Chang, 2015-11-03 21:06:14]

On 2015/11/03 21:01:12, Nico wrote:
> lgtm
> 
> (do you have any with / without goma build numbers? pdfium is fairly small,
> maybe it doesn't help all that much here…)

seems quite a bit faster on my machine:

ninja -C out/Debug  2339.21s user 85.26s system 3043% cpu 1:19.66 total

vs

ninja -C out/Debug -j400  18.54s user 4.67s system 63% cpu 36.324 total

[Oliver Chang, 2015-11-03 21:09:23]

Committed patchset #4 (id:60001) manually as
e35b445bee90390ea09f334cbff4a6220537bbda (presubmit successful).