Basic implementation of @apply

Basic implementation of @apply

This patch adds an initial implementation of @apply. Aside from setting
custom properties from an @apply block, all the other features of @apply
should be implemented.

The implementation strategy is similar to CSS custom properties, in that
we have a special CSSPropertyID value (CSSPropertyApplyAtRule) and store
the rules in StylePropertySets alongside regular declarations.

CSSVariableData is now able to cache a StylePropertySet object so we can
avoid having to re-parse the custom property sets across multiple style
recalcs. Note that this only helps for custom properties with no var()
references or @apply rules, as otherwise we'd create a new object every
style recalc.

The CSSOM interface for @apply implemented here differs from the current
spec draft. Instead of exposing @apply rules by changing CSSStyleRule to
inherit CSSGroupingRule, we instead treat them as regular declarations.
This has some weirdness in that CSSStyleDeclaration.item(i) can return a
value "@apply", which getPropertyValue won't accept. We need to at some
point work out the best behaviors for interfacing with the CSSOM.

As discussed with shans@, we allow @apply rules inside custom properties
and have them resolved when we resolve variables. They behave similarly
to var() references, and also contribute to cycle detection.

https://groups.google.com/a/chromium.org/forum/?fromgroups#!topic/blink-dev/Wc71ungGdn4
https://tabatkins.github.io/specs/css-apply-rule/

BUG=586974
Committed: https://crrev.com/39709d9f02fcb5c6b746e773b6c48b8e6855819e
Cr-Commit-Position: refs/heads/master@{#378108}

[Timothy Loh, 2016-02-23 00:33:19]

Description was changed from

==========
wip
==========

to

==========
Basic implementation of @apply

This patch adds an initial implementation of @apply. Aside from setting
custom properties from an @apply block, all the other features of @apply
should be implemented.

https://groups.google.com/a/chromium.org/forum/?fromgroups#!topic/blink-dev/W...
https://tabatkins.github.io/specs/css-apply-rule/
==========

[Timothy Loh, 2016-02-23 00:33:34]

Patchset #1 (id:1) has been deleted

[Timothy Loh, 2016-02-23 00:33:42]

Patchset #1 (id:20001) has been deleted

[Timothy Loh, 2016-02-23 00:34:23]

Patchset #1 (id:40001) has been deleted

[Timothy Loh, 2016-02-23 00:34:31]

Patchset #1 (id:60001) has been deleted

[Timothy Loh, 2016-02-23 00:46:59]

Description was changed from

==========
Basic implementation of @apply

This patch adds an initial implementation of @apply. Aside from setting
custom properties from an @apply block, all the other features of @apply
should be implemented.

https://groups.google.com/a/chromium.org/forum/?fromgroups#!topic/blink-dev/W...
https://tabatkins.github.io/specs/css-apply-rule/
==========

to

==========
Basic implementation of @apply

This patch adds an initial implementation of @apply. Aside from setting
custom properties from an @apply block, all the other features of @apply
should be implemented.

The implementation strategy is similar to CSS custom properties, in that
we have a special CSSPropertyID value (CSSPropertyApplyAtRule) and store
the rules in StylePropertySets alongside regular declarations.

CSSVariableData is now able to cache a StylePropertySet object so we can
avoid having to re-parse the custom property sets across multiple style
recalcs. Note that this only helps for custom properties with no var()
references or @apply rules, as otherwise we'd create a new object every
style recalc.

The CSSOM interface for @apply implemented here differs from the current
spec draft. Instead of exposing @apply rules by changing CSSStyleRule to
inherit CSSGroupingRule, we instead treat them as regular declarations.
This has some weirdness in that CSSStyleDeclaration.item(i) can return a
value "@apply", which getPropertyValue won't accept. We need to at some
point work out the best behaviors for interfacing with the CSSOM.

As discussed with shans@, we allow @apply rules inside custom properties
and have them resolved when we resolve variables. They behave similarly
to var() references, and also contribute to cycle detection.

https://groups.google.com/a/chromium.org/forum/?fromgroups#!topic/blink-dev/W...
https://tabatkins.github.io/specs/css-apply-rule/



TODO: should we allow them in regular properties? I think the code will
allow something like this:
  --green: {green};
  --foo: solid 5px;
  border: var(--foo) @apply --green;
==========

[Timothy Loh, 2016-02-23 00:47:00]

timloh@chromium.org changed reviewers:
+ dstockwell@chromium.org, shans@chromium.org

[Timothy Loh, 2016-02-23 00:47:20]

Patchset #1 (id:80001) has been deleted

[Timothy Loh, 2016-02-23 00:47:53]

Description was changed from

==========
Basic implementation of @apply

This patch adds an initial implementation of @apply. Aside from setting
custom properties from an @apply block, all the other features of @apply
should be implemented.

The implementation strategy is similar to CSS custom properties, in that
we have a special CSSPropertyID value (CSSPropertyApplyAtRule) and store
the rules in StylePropertySets alongside regular declarations.

CSSVariableData is now able to cache a StylePropertySet object so we can
avoid having to re-parse the custom property sets across multiple style
recalcs. Note that this only helps for custom properties with no var()
references or @apply rules, as otherwise we'd create a new object every
style recalc.

The CSSOM interface for @apply implemented here differs from the current
spec draft. Instead of exposing @apply rules by changing CSSStyleRule to
inherit CSSGroupingRule, we instead treat them as regular declarations.
This has some weirdness in that CSSStyleDeclaration.item(i) can return a
value "@apply", which getPropertyValue won't accept. We need to at some
point work out the best behaviors for interfacing with the CSSOM.

As discussed with shans@, we allow @apply rules inside custom properties
and have them resolved when we resolve variables. They behave similarly
to var() references, and also contribute to cycle detection.

https://groups.google.com/a/chromium.org/forum/?fromgroups#!topic/blink-dev/W...
https://tabatkins.github.io/specs/css-apply-rule/



TODO: should we allow them in regular properties? I think the code will
allow something like this:
  --green: {green};
  --foo: solid 5px;
  border: var(--foo) @apply --green;
==========

to

==========
Basic implementation of @apply

This patch adds an initial implementation of @apply. Aside from setting
custom properties from an @apply block, all the other features of @apply
should be implemented.

The implementation strategy is similar to CSS custom properties, in that
we have a special CSSPropertyID value (CSSPropertyApplyAtRule) and store
the rules in StylePropertySets alongside regular declarations.

CSSVariableData is now able to cache a StylePropertySet object so we can
avoid having to re-parse the custom property sets across multiple style
recalcs. Note that this only helps for custom properties with no var()
references or @apply rules, as otherwise we'd create a new object every
style recalc.

The CSSOM interface for @apply implemented here differs from the current
spec draft. Instead of exposing @apply rules by changing CSSStyleRule to
inherit CSSGroupingRule, we instead treat them as regular declarations.
This has some weirdness in that CSSStyleDeclaration.item(i) can return a
value "@apply", which getPropertyValue won't accept. We need to at some
point work out the best behaviors for interfacing with the CSSOM.

As discussed with shans@, we allow @apply rules inside custom properties
and have them resolved when we resolve variables. They behave similarly
to var() references, and also contribute to cycle detection.

https://groups.google.com/a/chromium.org/forum/?fromgroups#!topic/blink-dev/W...
https://tabatkins.github.io/specs/css-apply-rule/
==========

[Timothy Loh, 2016-02-23 00:48:23]

Description was changed from

==========
Basic implementation of @apply

This patch adds an initial implementation of @apply. Aside from setting
custom properties from an @apply block, all the other features of @apply
should be implemented.

The implementation strategy is similar to CSS custom properties, in that
we have a special CSSPropertyID value (CSSPropertyApplyAtRule) and store
the rules in StylePropertySets alongside regular declarations.

CSSVariableData is now able to cache a StylePropertySet object so we can
avoid having to re-parse the custom property sets across multiple style
recalcs. Note that this only helps for custom properties with no var()
references or @apply rules, as otherwise we'd create a new object every
style recalc.

The CSSOM interface for @apply implemented here differs from the current
spec draft. Instead of exposing @apply rules by changing CSSStyleRule to
inherit CSSGroupingRule, we instead treat them as regular declarations.
This has some weirdness in that CSSStyleDeclaration.item(i) can return a
value "@apply", which getPropertyValue won't accept. We need to at some
point work out the best behaviors for interfacing with the CSSOM.

As discussed with shans@, we allow @apply rules inside custom properties
and have them resolved when we resolve variables. They behave similarly
to var() references, and also contribute to cycle detection.

https://groups.google.com/a/chromium.org/forum/?fromgroups#!topic/blink-dev/W...
https://tabatkins.github.io/specs/css-apply-rule/
==========

to

==========
Basic implementation of @apply

This patch adds an initial implementation of @apply. Aside from setting
custom properties from an @apply block, all the other features of @apply
should be implemented.

The implementation strategy is similar to CSS custom properties, in that
we have a special CSSPropertyID value (CSSPropertyApplyAtRule) and store
the rules in StylePropertySets alongside regular declarations.

CSSVariableData is now able to cache a StylePropertySet object so we can
avoid having to re-parse the custom property sets across multiple style
recalcs. Note that this only helps for custom properties with no var()
references or @apply rules, as otherwise we'd create a new object every
style recalc.

The CSSOM interface for @apply implemented here differs from the current
spec draft. Instead of exposing @apply rules by changing CSSStyleRule to
inherit CSSGroupingRule, we instead treat them as regular declarations.
This has some weirdness in that CSSStyleDeclaration.item(i) can return a
value "@apply", which getPropertyValue won't accept. We need to at some
point work out the best behaviors for interfacing with the CSSOM.

As discussed with shans@, we allow @apply rules inside custom properties
and have them resolved when we resolve variables. They behave similarly
to var() references, and also contribute to cycle detection.

https://groups.google.com/a/chromium.org/forum/?fromgroups#!topic/blink-dev/W...
https://tabatkins.github.io/specs/css-apply-rule/

BUG=586974
==========

[Timothy Loh, 2016-02-23 00:50:36]

Should be ready for a first look. I just realized we probably allow some weird
stuff like @apply inside regular property declarations, we should probably think
about that..

(untested, but I think this will actually work lol)
  --green: {green};
  --foo: solid 5px;
  border: var(--foo) @apply --green;

[dstockwell, 2016-02-25 23:27:12]

lgtm

[Timothy Loh, 2016-02-25 23:45:33]

timloh@chromium.org changed reviewers:
+ noel@google.com

[Timothy Loh, 2016-02-25 23:45:33]

+noel for platform OWNERS (I touched RuntimeEnabledFeatures.in)

[Timothy Loh, 2016-02-26 04:12:58]

timloh@chromium.org changed reviewers:
+ haraken@chromium.org

[Timothy Loh, 2016-02-26 04:12:59]

haraken, could you have a look for RuntimeEnabledFeatures.in? thanks!

[haraken, 2016-02-26 08:31:04]

On 2016/02/26 04:12:59, Timothy Loh wrote:
> haraken, could you have a look for RuntimeEnabledFeatures.in? thanks!

platform/ LGTM.

[Timothy Loh, 2016-02-27 02:34:10]

The CQ bit was checked by timloh@chromium.org

[Timothy Loh, 2016-02-27 02:34:11]

The patchset sent to the CQ was uploaded after l-g-t-m from
dstockwell@chromium.org
Link to the patchset: https://codereview.chromium.org/1645433002/#ps240001
(title: "fix expted.txt for failing test")

[commit-bot: I haz the power, 2016-02-27 02:36:27]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1645433002/240001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1645433002/240001

[commit-bot: I haz the power, 2016-02-27 03:53:13]

Description was changed from

==========
Basic implementation of @apply

This patch adds an initial implementation of @apply. Aside from setting
custom properties from an @apply block, all the other features of @apply
should be implemented.

The implementation strategy is similar to CSS custom properties, in that
we have a special CSSPropertyID value (CSSPropertyApplyAtRule) and store
the rules in StylePropertySets alongside regular declarations.

CSSVariableData is now able to cache a StylePropertySet object so we can
avoid having to re-parse the custom property sets across multiple style
recalcs. Note that this only helps for custom properties with no var()
references or @apply rules, as otherwise we'd create a new object every
style recalc.

The CSSOM interface for @apply implemented here differs from the current
spec draft. Instead of exposing @apply rules by changing CSSStyleRule to
inherit CSSGroupingRule, we instead treat them as regular declarations.
This has some weirdness in that CSSStyleDeclaration.item(i) can return a
value "@apply", which getPropertyValue won't accept. We need to at some
point work out the best behaviors for interfacing with the CSSOM.

As discussed with shans@, we allow @apply rules inside custom properties
and have them resolved when we resolve variables. They behave similarly
to var() references, and also contribute to cycle detection.

https://groups.google.com/a/chromium.org/forum/?fromgroups#!topic/blink-dev/W...
https://tabatkins.github.io/specs/css-apply-rule/

BUG=586974
==========

to

==========
Basic implementation of @apply

This patch adds an initial implementation of @apply. Aside from setting
custom properties from an @apply block, all the other features of @apply
should be implemented.

The implementation strategy is similar to CSS custom properties, in that
we have a special CSSPropertyID value (CSSPropertyApplyAtRule) and store
the rules in StylePropertySets alongside regular declarations.

CSSVariableData is now able to cache a StylePropertySet object so we can
avoid having to re-parse the custom property sets across multiple style
recalcs. Note that this only helps for custom properties with no var()
references or @apply rules, as otherwise we'd create a new object every
style recalc.

The CSSOM interface for @apply implemented here differs from the current
spec draft. Instead of exposing @apply rules by changing CSSStyleRule to
inherit CSSGroupingRule, we instead treat them as regular declarations.
This has some weirdness in that CSSStyleDeclaration.item(i) can return a
value "@apply", which getPropertyValue won't accept. We need to at some
point work out the best behaviors for interfacing with the CSSOM.

As discussed with shans@, we allow @apply rules inside custom properties
and have them resolved when we resolve variables. They behave similarly
to var() references, and also contribute to cycle detection.

https://groups.google.com/a/chromium.org/forum/?fromgroups#!topic/blink-dev/W...
https://tabatkins.github.io/specs/css-apply-rule/

BUG=586974
==========

[commit-bot: I haz the power, 2016-02-27 03:53:14]

Committed patchset #8 (id:240001)

[commit-bot: I haz the power, 2016-02-27 03:54:47]

Description was changed from

==========
Basic implementation of @apply

This patch adds an initial implementation of @apply. Aside from setting
custom properties from an @apply block, all the other features of @apply
should be implemented.

The implementation strategy is similar to CSS custom properties, in that
we have a special CSSPropertyID value (CSSPropertyApplyAtRule) and store
the rules in StylePropertySets alongside regular declarations.

CSSVariableData is now able to cache a StylePropertySet object so we can
avoid having to re-parse the custom property sets across multiple style
recalcs. Note that this only helps for custom properties with no var()
references or @apply rules, as otherwise we'd create a new object every
style recalc.

The CSSOM interface for @apply implemented here differs from the current
spec draft. Instead of exposing @apply rules by changing CSSStyleRule to
inherit CSSGroupingRule, we instead treat them as regular declarations.
This has some weirdness in that CSSStyleDeclaration.item(i) can return a
value "@apply", which getPropertyValue won't accept. We need to at some
point work out the best behaviors for interfacing with the CSSOM.

As discussed with shans@, we allow @apply rules inside custom properties
and have them resolved when we resolve variables. They behave similarly
to var() references, and also contribute to cycle detection.

https://groups.google.com/a/chromium.org/forum/?fromgroups#!topic/blink-dev/W...
https://tabatkins.github.io/specs/css-apply-rule/

BUG=586974
==========

to

==========
Basic implementation of @apply

This patch adds an initial implementation of @apply. Aside from setting
custom properties from an @apply block, all the other features of @apply
should be implemented.

The implementation strategy is similar to CSS custom properties, in that
we have a special CSSPropertyID value (CSSPropertyApplyAtRule) and store
the rules in StylePropertySets alongside regular declarations.

CSSVariableData is now able to cache a StylePropertySet object so we can
avoid having to re-parse the custom property sets across multiple style
recalcs. Note that this only helps for custom properties with no var()
references or @apply rules, as otherwise we'd create a new object every
style recalc.

The CSSOM interface for @apply implemented here differs from the current
spec draft. Instead of exposing @apply rules by changing CSSStyleRule to
inherit CSSGroupingRule, we instead treat them as regular declarations.
This has some weirdness in that CSSStyleDeclaration.item(i) can return a
value "@apply", which getPropertyValue won't accept. We need to at some
point work out the best behaviors for interfacing with the CSSOM.

As discussed with shans@, we allow @apply rules inside custom properties
and have them resolved when we resolve variables. They behave similarly
to var() references, and also contribute to cycle detection.

https://groups.google.com/a/chromium.org/forum/?fromgroups#!topic/blink-dev/W...
https://tabatkins.github.io/specs/css-apply-rule/

BUG=586974

Committed: https://crrev.com/39709d9f02fcb5c6b746e773b6c48b8e6855819e
Cr-Commit-Position: refs/heads/master@{#378108}
==========

[commit-bot: I haz the power, 2016-02-27 03:54:48]

Patchset 8 (id:??) landed as
https://crrev.com/39709d9f02fcb5c6b746e773b6c48b8e6855819e
Cr-Commit-Position: refs/heads/master@{#378108}

[drott, 2016-03-17 07:38:43]

drott@chromium.org changed reviewers:
+ drott@chromium.org

[drott, 2016-03-17 07:38:44]

https://codereview.chromium.org/1645433002/diff/240001/third_party/WebKit/Sou...
File third_party/WebKit/Source/core/frame/UseCounter.cpp (right):

https://codereview.chromium.org/1645433002/diff/240001/third_party/WebKit/Sou...
third_party/WebKit/Source/core/frame/UseCounter.cpp:572: // 3. Run the
update_use_counter_css.py script in
Could you run this to update the histograms.xml file?