Bug 1454165 - Make :host() and ::slotted() account for the inner sele…

…ctor's specificity. r=xidorn

As resolved in w3c/csswg-drafts#1915.

Differential Revision: https://phabricator.services.mozilla.com/D1849

UltraBlame original commit: ca14c36e4280927a10e43e95b8f459e767fc8178

servo/components/selectors/builder.rs

@@ -270,7 +270,10 @@ std
 ops
 :
 :
+{
+AddAssign
 Add
+}
 ;
 use
 std
@@ -1831,6 +1834,55 @@ element_selectors
 u32
 }
 impl
+AddAssign
+for
+Specificity
+{
+#
+[
+inline
+]
+fn
+add_assign
+(
+&
+mut
+self
+rhs
+:
+Self
+)
+{
+self
+.
+id_selectors
++
+=
+rhs
+.
+id_selectors
+;
+self
+.
+class_like_selectors
++
+=
+rhs
+.
+class_like_selectors
+;
+self
+.
+element_selectors
++
+=
+rhs
+.
+element_selectors
+;
+}
+}
+impl
 Add
 for
 Specificity
@@ -1919,6 +1971,10 @@ u32
 for
 Specificity
 {
+#
+[
+inline
+]
 fn
 from
 (
@@ -1983,6 +2039,10 @@ Specificity
 for
 u32
 {
+#
+[
+inline
+]
 fn
 from
 (
@@ -2184,42 +2244,106 @@ builder
 )
 ;
 }
-/
-/
-FIXME
+Component
+:
+:
+PseudoElement
 (
-emilio
+.
+.
 )
+|
+Component
 :
-Spec
-doesn
-'
-t
-define
-any
-particular
+:
+LocalName
+(
+.
+.
+)
+=
+>
+{
 specificity
-for
+.
+element_selectors
++
+=
+1
+}
+Component
+:
+:
+Slotted
+(
+ref
+selector
+)
+=
+>
+{
+specificity
+.
+element_selectors
++
+=
+1
+;
 /
 /
+Note
+that
+due
+to
+the
+way
 :
 :
 slotted
-(
-)
+works
+we
+only
+compete
+with
+/
+/
+other
+:
+:
+slotted
+rules
 so
-apply
 the
-general
+above
 rule
+doesn
+'
+t
+really
+/
+/
+matter
+but
+we
+do
+it
+still
 for
-pseudos
-per
-:
+consistency
+with
+other
+/
+/
+pseudo
+-
+elements
+.
 /
 /
 /
 /
+See
+:
 https
 :
 /
@@ -2237,62 +2361,90 @@ drafts
 issues
 /
 1915
-/
-/
-/
-/
-Though
-other
-engines
-compute
-it
-dynamically
-so
-maybe
-we
-should
-/
-/
-do
-that
-instead
-eventually
-.
-Component
+*
+specificity
++
+=
+Specificity
 :
 :
-Slotted
+from
 (
+selector
 .
-.
-)
-|
-Component
-:
-:
-PseudoElement
+specificity
 (
-.
-.
 )
-|
+)
+;
+}
 Component
 :
 :
-LocalName
+Host
 (
-.
-.
+ref
+selector
 )
 =
 >
 {
 specificity
 .
-element_selectors
+class_like_selectors
 +
 =
 1
+;
+if
+let
+Some
+(
+ref
+selector
+)
+=
+*
+selector
+{
+/
+/
+See
+:
+https
+:
+/
+/
+github
+.
+com
+/
+w3c
+/
+csswg
+-
+drafts
+/
+issues
+/
+1915
+*
+specificity
++
+=
+Specificity
+:
+:
+from
+(
+selector
+.
+specificity
+(
+)
+)
+;
+}
 }
 Component
 :
@@ -2304,12 +2456,15 @@ ID
 )
 =
 >
+{
 specificity
 .
 id_selectors
 +
 =
 1
+;
+}
 Component
 :
 :
@@ -2379,15 +2534,6 @@ Scope
 Component
 :
 :
-Host
-(
-.
-.
-)
-|
-Component
-:
-:
 NthChild
 (
 .
@@ -2446,12 +2592,15 @@ NonTSPseudoClass
 )
 =
 >
+{
 specificity
 .
 class_like_selectors
 +
 =
 1
+;
+}
 Component
 :
 :