Don't add to siblingRules for features left of ::slotted.

Don't add to siblingRules for features left of ::slotted.

Like for ::content distributed elements in shadow dom v0, slotted
elements do not share style if they are assigned/distributed to
different slots. Hence, we don't need to add rules to siblingRules when
the combinators or simple selectors are left of the ::slotted pseudo.

We need to add "::slotted(:nth-child(odd)" to siblingRules, but not
".a + ::slotted(.b)" nor ":nth-of-type(3)::slotted(*)".

Similarly, nothing left of :host or :host-context will ever match, so
we can treat those the same way. Selectors like "div + :host" or
":only-child:host-context(.a)" will never match. There is nothing in
the CSS Scoping spec which says they're invalid, hence they're not
dropped.

There was a bug in https://codereview.chromium.org/1683923003/ which
made us detect adjacent combinators before we had noticed the ::content
following it. The detection of sibling dependent pseudo classes like
:emtpy, :nth-child, etc and adjacent combinators have therefore been
split in this CL so that we handle the simple selectors in a compound
before we handle the combinator. Corresponding unit tests have been
added.

R=kochi@chromium.org,hayato@chromium.org

Committed: https://crrev.com/593fca77e1a391c59c4cf14a5ecf54c35e2cef65
Cr-Commit-Position: refs/heads/master@{#375531}

[rune, 2016-02-16 00:18:03]

The CQ bit was checked by rune@opera.com to run a CQ dry run

[commit-bot: I haz the power, 2016-02-16 00:18:10]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1695393002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1695393002/1

[commit-bot: I haz the power, 2016-02-16 01:26:43]

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

[commit-bot: I haz the power, 2016-02-16 01:26:44]

Dry run: This issue passed the CQ dry run.

[kochi, 2016-02-16 08:00:57]

LGTM

[rune, 2016-02-16 08:19:26]

The CQ bit was checked by rune@opera.com

[commit-bot: I haz the power, 2016-02-16 08:19:46]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1695393002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1695393002/1

[commit-bot: I haz the power, 2016-02-16 08:25:02]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-02-16 22:51:43]

Description was changed from

==========
Don't add to siblingRules for features left of ::slotted.

Like for ::content distributed elements in shadow dom v0, slotted
elements do not share style if they are assigned/distributed to
different slots. Hence, we don't need to add rules to siblingRules when
the combinators or simple selectors are left of the ::slotted pseudo.

We need to add "::slotted(:nth-child(odd)" to siblingRules, but not
".a + ::slotted(.b)" nor ":nth-of-type(3)::slotted(*)".

Similarly, nothing left of :host or :host-context will ever match, so
we can treat those the same way. Selectors like "div + :host" or
":only-child:host-context(.a)" will never match. There is nothing in
the CSS Scoping spec which says they're invalid, hence they're not
dropped.

There was a bug in https://codereview.chromium.org/1683923003/ which
made us detect adjacent combinators before we had noticed the ::content
following it. The detection of sibling dependent pseudo classes like
:emtpy, :nth-child, etc and adjacent combinators have therefore been
split in this CL so that we handle the simple selectors in a compound
before we handle the combinator. Corresponding unit tests have been
added.

R=kochi@chromium.org,hayato@chromium.org
==========

to

==========
Don't add to siblingRules for features left of ::slotted.

Like for ::content distributed elements in shadow dom v0, slotted
elements do not share style if they are assigned/distributed to
different slots. Hence, we don't need to add rules to siblingRules when
the combinators or simple selectors are left of the ::slotted pseudo.

We need to add "::slotted(:nth-child(odd)" to siblingRules, but not
".a + ::slotted(.b)" nor ":nth-of-type(3)::slotted(*)".

Similarly, nothing left of :host or :host-context will ever match, so
we can treat those the same way. Selectors like "div + :host" or
":only-child:host-context(.a)" will never match. There is nothing in
the CSS Scoping spec which says they're invalid, hence they're not
dropped.

There was a bug in https://codereview.chromium.org/1683923003/ which
made us detect adjacent combinators before we had noticed the ::content
following it. The detection of sibling dependent pseudo classes like
:emtpy, :nth-child, etc and adjacent combinators have therefore been
split in this CL so that we handle the simple selectors in a compound
before we handle the combinator. Corresponding unit tests have been
added.

R=kochi@chromium.org,hayato@chromium.org

Committed: https://crrev.com/593fca77e1a391c59c4cf14a5ecf54c35e2cef65
Cr-Commit-Position: refs/heads/master@{#375531}
==========

[commit-bot: I haz the power, 2016-02-16 22:51:44]

Patchset 1 (id:??) landed as
https://crrev.com/593fca77e1a391c59c4cf14a5ecf54c35e2cef65
Cr-Commit-Position: refs/heads/master@{#375531}