GN: make libwebp an optional dependency

GN: make libwebp an optional dependency

This will be handy for folks who don't have libwebp, like Fuchsia.

I convinced myself that this is done right by:
  - building in all three modes (default and explicitly set both ways);
  - looking at verbose Ninja logs to see the presence/lack of SK_HAS_WEBP_LIBRARY;
  - running dm -m Codec, which passes with libwebp and segfault without it.

If this is viable, I intend to make all third-party dependencies optional
and follow this pattern.  :skia should link and degrade gracefully without
any of //third_party.  It's okay for tools to have hard third-party 
dependencies; we just need them to get past the `gn gen` stage without them.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2270693004

Committed: https://skia.googlesource.com/skia/+/eb3c425f1b33836e116e8ed4eeb40e0c6d8dffb6

[mtklein_C, 2016-08-23 13:37:29]

Description was changed from

==========
GN: make libwebp an optional dependency

This will be handy for folks who don't have libwebp, like Fuchsia.

I convinced myself that this is done right by:
  - building in both modes;
  - looking at verbose Ninja logs to see the presence/lack of
SK_HAS_WEBP_LIBRARY;
  - running dm -m Codec, which passes with libwebp and segfault without it.

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

to

==========
GN: make libwebp an optional dependency

This will be handy for folks who don't have libwebp, like Fuchsia.

I convinced myself that this is done right by:
  - building in both modes;
  - looking at verbose Ninja logs to see the presence/lack of
SK_HAS_WEBP_LIBRARY;
  - running dm -m Codec, which passes with libwebp and segfault without it.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2270693004
==========

[mtklein_C, 2016-08-23 13:43:02]

Description was changed from

==========
GN: make libwebp an optional dependency

This will be handy for folks who don't have libwebp, like Fuchsia.

I convinced myself that this is done right by:
  - building in both modes;
  - looking at verbose Ninja logs to see the presence/lack of
SK_HAS_WEBP_LIBRARY;
  - running dm -m Codec, which passes with libwebp and segfault without it.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2270693004
==========

to

==========
GN: make libwebp an optional dependency

This will be handy for folks who don't have libwebp, like Fuchsia.

I convinced myself that this is done right by:
  - building in all three modes (default and explicitly set both ways);
  - looking at verbose Ninja logs to see the presence/lack of
SK_HAS_WEBP_LIBRARY;
  - running dm -m Codec, which passes with libwebp and segfault without it.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2270693004
==========

[mtklein_C, 2016-08-23 13:43:58]

Description was changed from

==========
GN: make libwebp an optional dependency

This will be handy for folks who don't have libwebp, like Fuchsia.

I convinced myself that this is done right by:
  - building in all three modes (default and explicitly set both ways);
  - looking at verbose Ninja logs to see the presence/lack of
SK_HAS_WEBP_LIBRARY;
  - running dm -m Codec, which passes with libwebp and segfault without it.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2270693004
==========

to

==========
GN: make libwebp an optional dependency

This will be handy for folks who don't have libwebp, like Fuchsia.

I convinced myself that this is done right by:
  - building in all three modes (default and explicitly set both ways);
  - looking at verbose Ninja logs to see the presence/lack of
SK_HAS_WEBP_LIBRARY;
  - running dm -m Codec, which passes with libwebp and segfault without it.

If this is viable, I intend to make all optional dependencies follow this
pattern.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2270693004
==========

[mtklein_C, 2016-08-23 13:44:02]

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

[commit-bot: I haz the power, 2016-08-23 13:44:11]

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

[mtklein_C, 2016-08-23 13:55:03]

Description was changed from

==========
GN: make libwebp an optional dependency

This will be handy for folks who don't have libwebp, like Fuchsia.

I convinced myself that this is done right by:
  - building in all three modes (default and explicitly set both ways);
  - looking at verbose Ninja logs to see the presence/lack of
SK_HAS_WEBP_LIBRARY;
  - running dm -m Codec, which passes with libwebp and segfault without it.

If this is viable, I intend to make all optional dependencies follow this
pattern.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2270693004
==========

to

==========
GN: make libwebp an optional dependency

This will be handy for folks who don't have libwebp, like Fuchsia.

I convinced myself that this is done right by:
  - building in all three modes (default and explicitly set both ways);
  - looking at verbose Ninja logs to see the presence/lack of
SK_HAS_WEBP_LIBRARY;
  - running dm -m Codec, which passes with libwebp and segfault without it.

If this is viable, I intend to make all third-party dependencies optional and
follow this pattern.  :skia should link and degrade gracefully without any of
//third_party.  It's okay for tools to have hard third-party dependencies; we
just need them to get past the `gn gen` stage without them.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2270693004
==========

[mtklein_C, 2016-08-23 13:55:17]

Description was changed from

==========
GN: make libwebp an optional dependency

This will be handy for folks who don't have libwebp, like Fuchsia.

I convinced myself that this is done right by:
  - building in all three modes (default and explicitly set both ways);
  - looking at verbose Ninja logs to see the presence/lack of
SK_HAS_WEBP_LIBRARY;
  - running dm -m Codec, which passes with libwebp and segfault without it.

If this is viable, I intend to make all third-party dependencies optional and
follow this pattern.  :skia should link and degrade gracefully without any of
//third_party.  It's okay for tools to have hard third-party dependencies; we
just need them to get past the `gn gen` stage without them.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2270693004
==========

to

==========
GN: make libwebp an optional dependency

This will be handy for folks who don't have libwebp, like Fuchsia.

I convinced myself that this is done right by:
  - building in all three modes (default and explicitly set both ways);
  - looking at verbose Ninja logs to see the presence/lack of
SK_HAS_WEBP_LIBRARY;
  - running dm -m Codec, which passes with libwebp and segfault without it.

If this is viable, I intend to make all third-party dependencies optional
and follow this pattern.  :skia should link and degrade gracefully without
any of //third_party.  It's okay for tools to have hard third-party 
dependencies; we just need them to get past the `gn gen` stage without them.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2270693004
==========

[mtklein_C, 2016-08-23 13:59:04]

mtklein@chromium.org changed reviewers:
+ anmittal@google.com, jcgregorio@google.com, msarett@google.com

[mtklein_C, 2016-08-23 13:59:05]

anmittal, will this work for Fuchsia?
jcgregorio, down with this general approach to third_party?
msarett, is this sane for Codec/Encoders?

[commit-bot: I haz the power, 2016-08-23 14:11:03]

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

[commit-bot: I haz the power, 2016-08-23 14:11:04]

Dry run: This issue passed the CQ dry run.

[msarett, 2016-08-23 14:13:51]

On 2016/08/23 13:59:05, mtklein_C wrote:
> anmittal, will this work for Fuchsia?
> jcgregorio, down with this general approach to third_party?
> msarett, is this sane for Codec/Encoders?

Codec lgtm.

"- running dm -m Codec, which passes with libwebp and segfault without it."

Just confirming, we seg fault (in test code) without libwebp even when
SK_HAS_WEBP_LIBRARY is not defined.

[jcgregorio, 2016-08-23 14:30:00]

On 2016/08/23 at 14:13:51, msarett wrote:
> On 2016/08/23 13:59:05, mtklein_C wrote:
> > anmittal, will this work for Fuchsia?
> > jcgregorio, down with this general approach to third_party?

LGTM. This looks great, so all the third_party libs will move to this format?

> > msarett, is this sane for Codec/Encoders?
> 
> Codec lgtm.
> 
> "- running dm -m Codec, which passes with libwebp and segfault without it."
> 
> Just confirming, we seg fault (in test code) without libwebp even when
SK_HAS_WEBP_LIBRARY is not defined.

[mtklein, 2016-08-23 14:33:38]

> Just confirming, we seg fault (in test code) without libwebp even when
> SK_HAS_WEBP_LIBRARY is not defined.

Right, the problem in this test is fixable.  It's just something like:
   REPORTER_ASSERT(r, codec);
   if (  f (codec, codec->info(), ...) ) { ... }

It's just not written to actually keep running if that REPORTER_ASSERT fails.

Ultimately I think this is fine.  I do not expect our tools to be useable except
by bots or developers who have run gclient sync inside skia/.

[mtklein_C, 2016-08-23 14:36:52]

> LGTM. This looks great, so all the third_party libs will move to this format?

That's my hope, yeah.

Gonna land this now and start fleshing out the rest.  Whether or not this fixes
Fuchsia's pain point, I can't imagine it makes things worse.

[mtklein_C, 2016-08-23 14:37:05]

The CQ bit was checked by mtklein@chromium.org

[commit-bot: I haz the power, 2016-08-23 14:37:19]

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, 2016-08-23 14:38:11]

Description was changed from

==========
GN: make libwebp an optional dependency

This will be handy for folks who don't have libwebp, like Fuchsia.

I convinced myself that this is done right by:
  - building in all three modes (default and explicitly set both ways);
  - looking at verbose Ninja logs to see the presence/lack of
SK_HAS_WEBP_LIBRARY;
  - running dm -m Codec, which passes with libwebp and segfault without it.

If this is viable, I intend to make all third-party dependencies optional
and follow this pattern.  :skia should link and degrade gracefully without
any of //third_party.  It's okay for tools to have hard third-party 
dependencies; we just need them to get past the `gn gen` stage without them.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2270693004
==========

to

==========
GN: make libwebp an optional dependency

This will be handy for folks who don't have libwebp, like Fuchsia.

I convinced myself that this is done right by:
  - building in all three modes (default and explicitly set both ways);
  - looking at verbose Ninja logs to see the presence/lack of
SK_HAS_WEBP_LIBRARY;
  - running dm -m Codec, which passes with libwebp and segfault without it.

If this is viable, I intend to make all third-party dependencies optional
and follow this pattern.  :skia should link and degrade gracefully without
any of //third_party.  It's okay for tools to have hard third-party 
dependencies; we just need them to get past the `gn gen` stage without them.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2270693004

Committed:
https://skia.googlesource.com/skia/+/eb3c425f1b33836e116e8ed4eeb40e0c6d8dffb6
==========

[commit-bot: I haz the power, 2016-08-23 14:38:12]

Committed patchset #2 (id:20001) as
https://skia.googlesource.com/skia/+/eb3c425f1b33836e116e8ed4eeb40e0c6d8dffb6

[anmittal, 2016-08-23 17:26:51]

On 2016/08/23 14:36:52, mtklein_C wrote:
> > LGTM. This looks great, so all the third_party libs will move to this
format?
> 
> That's my hope, yeah.
> 
> Gonna land this now and start fleshing out the rest.  Whether or not this
fixes
> Fuchsia's pain point, I can't imagine it makes things worse.

hey sorry for late comment, the fix works great for fuchsia. Thanks for making
this change :)

[anmittal, 2016-08-23 17:26:54]

On 2016/08/23 14:36:52, mtklein_C wrote:
> > LGTM. This looks great, so all the third_party libs will move to this
format?
> 
> That's my hope, yeah.
> 
> Gonna land this now and start fleshing out the rest.  Whether or not this
fixes
> Fuchsia's pain point, I can't imagine it makes things worse.

hey sorry for late comment, the fix works great for fuchsia. Thanks for making
this change :)