Bug 1838450 - Refine attribute handling. r=emilio

whatwg/dom#1176
https://dom.spec.whatwg.org/#concept-element-attributes-change-ext
"attribute change steps"  at https://html.spec.whatwg.org/multipage/popover.html#attr-popover

Differential Revision: https://phabricator.services.mozilla.com/D181880

UltraBlame original commit: 00b027478170756439b780282f9cfdf15edea985

dom/html/nsGenericHTMLElement.cpp

@@ -4568,38 +4568,29 @@ AfterSetPopoverAttr
 (
 )
 {
-const
-nsAttrValue
-*
-newValue
-=
-GetParsedAttr
-(
-nsGkAtoms
-:
-:
-popover
-)
-;
-const
-PopoverAttributeState
-newState
+auto
+mapPopoverState
 =
 [
-&
-newValue
 ]
 (
+const
+nsAttrValue
+*
+value
 )
+-
+>
+PopoverAttributeState
 {
 if
 (
-newValue
+value
 )
 {
 MOZ_ASSERT
 (
-newValue
+value
 -
 >
 Type
@@ -4622,7 +4613,7 @@ static_cast
 PopoverAttributeKeyword
 >
 (
-newValue
+value
 -
 >
 GetEnumValue
@@ -4682,7 +4673,19 @@ PopoverAttributeState
 None
 ;
 }
+;
+PopoverAttributeState
+newState
+=
+mapPopoverState
 (
+GetParsedAttr
+(
+nsGkAtoms
+:
+:
+popover
+)
 )
 ;
 const
@@ -4701,15 +4704,19 @@ newState
 oldState
 )
 {
-EnsurePopoverData
+PopoverPseudoStateUpdate
 (
+false
+true
 )
-.
-SetPopoverAttributeState
+;
+if
+(
+IsPopoverOpen
 (
-newState
 )
-;
+)
+{
 HidePopoverInternal
 (
 /
@@ -4733,36 +4740,52 @@ IgnoreErrors
 ;
 /
 /
-In
-case
-HidePopoverInternal
-changed
-the
-state
-keep
+Event
+handlers
+could
+have
+removed
 the
-corresponding
+popover
+attribute
+or
+changed
 /
 /
-changes
-and
-don
-'
-t
-overwrite
-anything
-here
+its
+value
 .
-if
-(
+/
+/
+https
+:
+/
+/
+github
+.
+com
+/
+whatwg
+/
+html
+/
+issues
+/
+9034
 newState
 =
-=
-GetPopoverAttributeState
+mapPopoverState
+(
+GetParsedAttr
 (
+nsGkAtoms
+:
+:
+popover
 )
 )
-{
+;
+}
 if
 (
 newState
@@ -4778,49 +4801,25 @@ None
 /
 HidePopoverInternal
 above
-didn
-'
-t
-remove
+could
+have
+removed
 the
-element
+popover
 from
 the
 top
 /
 /
 layer
-because
-in
-that
-call
-the
-element
-'
-s
-popover
-attribute
-state
-/
-/
-was
-already
-None
 .
-Revisit
-this
-when
-the
-spec
-is
-corrected
-/
-/
+if
+(
+GetPopoverData
 (
-bug
-1835811
 )
-.
+)
+{
 OwnerDoc
 (
 )
@@ -4832,6 +4831,7 @@ RemovePopoverFromTopLayer
 this
 )
 ;
+}
 ClearPopoverData
 (
 )
@@ -4859,16 +4859,18 @@ ShowPopup
 (
 )
 ?
-PopoverPseudoStateUpdate
+EnsurePopoverData
 (
-false
-true
+)
+.
+SetPopoverAttributeState
+(
+newState
 )
 ;
 }
 }
 }
-}
 void
 nsGenericHTMLElement
 :
@@ -20980,24 +20982,8 @@ ErrorResult
 aRv
 )
 {
-const
-PopoverData
-*
-data
-=
-GetPopoverData
-(
-)
-;
 if
 (
-!
-data
-|
-|
-data
--
->
 GetPopoverAttributeState
 (
 )
@@ -21009,18 +20995,6 @@ PopoverAttributeState
 None
 )
 {
-MOZ_ASSERT
-(
-!
-HasAttr
-(
-nsGkAtoms
-:
-:
-popover
-)
-)
-;
 aRv
 .
 ThrowNotSupportedError
@@ -21040,20 +21014,11 @@ return
 false
 ;
 }
-MOZ_ASSERT
+if
 (
-HasAttr
+GetPopoverData
 (
-nsGkAtoms
-:
-:
-popover
-)
 )
-;
-if
-(
-data
 -
 >
 GetPopoverVisibilityState