GN: add sources_when_disabled to optional

GN: add sources_when_disabled to optional

Also make sources_when_disabled and public_defines optional arguments.
These are the two mechanisms code uses to turn itself off...
probably at most one is ever used per optional.

Update fiddle to not crash when there's no PDF backend.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2292343003

Committed: https://skia.googlesource.com/skia/+/cd01b03df8acefbe0e8a37fa10b97d8a6fc0b992

[mtklein_C, 2016-08-30 21:10:39]

Description was changed from

==========
GN: add sources_when_disabled to optional

Also make sources_when_disabled and public_defines optional arguments.
These are the two mechanisms code uses to turn itself off...
probably at most one is ever used per optional.

Update fiddle to not crash when there's no PDF backend.

BUG=skia:
==========

to

==========
GN: add sources_when_disabled to optional

Also make sources_when_disabled and public_defines optional arguments.
These are the two mechanisms code uses to turn itself off...
probably at most one is ever used per optional.

Update fiddle to not crash when there's no PDF backend.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2292343003
==========

[mtklein_C, 2016-08-30 21:12:13]

The CQ bit was checked by mtklein@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-08-30 21:12:19]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-08-30 21:35:49]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-08-30 21:35:50]

Dry run: This issue passed the CQ dry run.

[hal.canary, 2016-08-30 23:05:05]

halcanary@google.com changed reviewers:
+ halcanary@google.com

[hal.canary, 2016-08-30 23:05:05]

lgtm

this is better.
lgtm

[mtklein, 2016-08-31 11:46:34]

The CQ bit was checked by mtklein@google.com

[commit-bot: I haz the power, 2016-08-31 11:46:37]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-08-31 11:58:23]

Description was changed from

==========
GN: add sources_when_disabled to optional

Also make sources_when_disabled and public_defines optional arguments.
These are the two mechanisms code uses to turn itself off...
probably at most one is ever used per optional.

Update fiddle to not crash when there's no PDF backend.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2292343003
==========

to

==========
GN: add sources_when_disabled to optional

Also make sources_when_disabled and public_defines optional arguments.
These are the two mechanisms code uses to turn itself off...
probably at most one is ever used per optional.

Update fiddle to not crash when there's no PDF backend.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2292343003

Committed:
https://skia.googlesource.com/skia/+/cd01b03df8acefbe0e8a37fa10b97d8a6fc0b992
==========

[commit-bot: I haz the power, 2016-08-31 11:58:24]

Committed patchset #1 (id:1) as
https://skia.googlesource.com/skia/+/cd01b03df8acefbe0e8a37fa10b97d8a6fc0b992