Update 4f linear gradient selection heuristic

Update 4f linear gradient selection heuristic

Use the 4f context when

  * dest type is 4f
  * there's no perpective

Keeping the define and testing flag overrides for now.

R=reed@google.com,herb@google.com
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1725793003

Committed: https://skia.googlesource.com/skia/+/55430a620762e882c2b3018c57f9a7d51cf16071

[f(malita), 2016-02-23 14:35:09]

Description was changed from

==========
Update 4f linear gradient selection heuristic

Use the 4f context when

  * dest type is 4f
  * there's no perpective

Keeping the define and testing flag overrides for now.

R=reed@google.com,herb@google.com
==========

to

==========
Update 4f linear gradient selection heuristic

Use the 4f context when

  * dest type is 4f
  * there's no perpective

Keeping the define and testing flag overrides for now.

R=reed@google.com,herb@google.com
GOLD_TRYBOT_URL=
https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&is...
==========

[f(malita), 2016-02-23 14:39:27]

This lets us test 4f gradients in SampleApp by switching to S32/F16.

[f(malita), 2016-02-23 14:39:56]

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

[commit-bot: I haz the power, 2016-02-23 14:40:01]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1725793003/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1725793003/20001

[commit-bot: I haz the power, 2016-02-23 14:52:04]

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

[commit-bot: I haz the power, 2016-02-23 14:52:05]

Dry run: Try jobs failed on following builders:
  Test-Ubuntu-GCC-GCE-CPU-AVX2-x86_64-Release-Shared-Trybot on client.skia
(JOB_FAILED,
http://build.chromium.org/p/client.skia/builders/Test-Ubuntu-GCC-GCE-CPU-AVX2...)

[reed1, 2016-02-23 15:43:34]

Knowing that the blitter still might call shadeSpan4f() even if this picks the
old subclass, lgtm. Should not be a functional problem since shadeSpan4f()
"works" for all shaders, even legacy ones (just not optimally).

[f(malita), 2016-02-23 18:08:18]

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

[commit-bot: I haz the power, 2016-02-23 18:08:24]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1725793003/40001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1725793003/40001

[f(malita), 2016-02-23 18:19:46]

I had to relax the Color4f_shader unit test tolerance to accommodate the new
version, PTAL.

(When drawing to a PMColor dest, we scale the start color + color gradient and
then interpolate over the span => precision deviations are cumulative.  To avoid
this, we'd have to apply the 255 scale after interpolation, but that's
significantly less efficient.  I think it's OK to relax the tolerance for now,
WDYT?)

[f(malita), 2016-02-23 18:21:19]

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

[commit-bot: I haz the power, 2016-02-23 18:21:25]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1725793003/60001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1725793003/60001

[commit-bot: I haz the power, 2016-02-23 18:36:21]

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

[commit-bot: I haz the power, 2016-02-23 18:36:21]

Dry run: This issue passed the CQ dry run.

[f(malita), 2016-02-23 21:25:23]

The CQ bit was checked by fmalita@chromium.org

[f(malita), 2016-02-23 21:25:24]

The patchset sent to the CQ was uploaded after l-g-t-m from reed@google.com
Link to the patchset: https://codereview.chromium.org/1725793003/#ps60001
(title: "spelling")

[commit-bot: I haz the power, 2016-02-23 21:25:29]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1725793003/60001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1725793003/60001

[commit-bot: I haz the power, 2016-02-23 21:26:31]

Description was changed from

==========
Update 4f linear gradient selection heuristic

Use the 4f context when

  * dest type is 4f
  * there's no perpective

Keeping the define and testing flag overrides for now.

R=reed@google.com,herb@google.com
GOLD_TRYBOT_URL=
https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&is...
==========

to

==========
Update 4f linear gradient selection heuristic

Use the 4f context when

  * dest type is 4f
  * there's no perpective

Keeping the define and testing flag overrides for now.

R=reed@google.com,herb@google.com
GOLD_TRYBOT_URL=
https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&is...

Committed:
https://skia.googlesource.com/skia/+/55430a620762e882c2b3018c57f9a7d51cf16071
==========

[commit-bot: I haz the power, 2016-02-23 21:26:32]

Committed patchset #4 (id:60001) as
https://skia.googlesource.com/skia/+/55430a620762e882c2b3018c57f9a7d51cf16071