[4fGradient] Veto blitters for non-opaque paints

[4fGradient] Veto blitters for non-opaque paints

The current blitters don't support SrcOver, so we must ensure the colors
are opaque.  Checking shader.colorsAreOpaque() is not enough as it
doesn't reflect the paint alpha.

Instead we should check for context flags & kOpaqueAlpha_Flag, which is
only set when both the color stops AND the paint are opaque.

R=reed@google.com
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1870773002

Committed: https://skia.googlesource.com/skia/+/eadf3cf899d87b9c96fb7ede5c8eb54f63900193

[f(malita), 2016-04-07 19:49:15]

Description was changed from

==========
[4fGradient] Veto blitters for non-opaque paints

The current blitters don't support SrcOver, so we must ensure the colors
are opaque.  Checking shader.colorsAreOpaque() is not enough as it
doesn't reflect the paint alpha.

Instead we should check for context flags & kOpaqueAlpha_Flag, which is
only set when both the color stops AND the paint are opaque.

R=reed@google.com
==========

to

==========
[4fGradient] Veto blitters for non-opaque paints

The current blitters don't support SrcOver, so we must ensure the colors
are opaque.  Checking shader.colorsAreOpaque() is not enough as it
doesn't reflect the paint alpha.

Instead we should check for context flags & kOpaqueAlpha_Flag, which is
only set when both the color stops AND the paint are opaque.

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

[f(malita), 2016-04-07 19:50:20]

The CQ bit was checked by fmalita@chromium.org

[commit-bot: I haz the power, 2016-04-07 19:50:25]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1870773002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1870773002/1

[commit-bot: I haz the power, 2016-04-07 19:50:26]

Note for Reviewers:
The CQ is waiting for an approval.
If you believe that the CL is not ready yet, or if you would like to L-G-T-M
with comments then please uncheck the CQ checkbox.

Waiting for LGTM from valid reviewer(s) till 2016-04-08 01:50 UTC

[reed1, 2016-04-07 19:55:48]

lgtm

[commit-bot: I haz the power, 2016-04-07 20:16:16]

Description was changed from

==========
[4fGradient] Veto blitters for non-opaque paints

The current blitters don't support SrcOver, so we must ensure the colors
are opaque.  Checking shader.colorsAreOpaque() is not enough as it
doesn't reflect the paint alpha.

Instead we should check for context flags & kOpaqueAlpha_Flag, which is
only set when both the color stops AND the paint are opaque.

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

to

==========
[4fGradient] Veto blitters for non-opaque paints

The current blitters don't support SrcOver, so we must ensure the colors
are opaque.  Checking shader.colorsAreOpaque() is not enough as it
doesn't reflect the paint alpha.

Instead we should check for context flags & kOpaqueAlpha_Flag, which is
only set when both the color stops AND the paint are opaque.

R=reed@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/+/eadf3cf899d87b9c96fb7ede5c8eb54f63900193
==========

[commit-bot: I haz the power, 2016-04-07 20:16:17]

Committed patchset #1 (id:1) as
https://skia.googlesource.com/skia/+/eadf3cf899d87b9c96fb7ede5c8eb54f63900193