[css-view-transition-1] Simplify handling of ::view-transition

Author: Psychpsyo

css-view-transitions-1/Overview.bs

@@ -689,8 +689,12 @@ urlPrefix: https://wicg.github.io/navigation-api/; type: interface;
 	Its [=originating element=] is the document's [=document element=],
 	and its [=containing block=] is the [=snapshot containing block=].
 
+	This element is only rendered when it has children.
+
 	Note: This element serves as the [=tree/parent=] of all ''::view-transition-group()'' pseudo-elements.
 
+	Note: The position of this element within the [=document element=] does not matter, as its [=containing block=] is the [=snapshot containing block=].
+
 ### View Transition Named Subtree Root: the ''::view-transition-group()'' pseudo-element ### {#::view-transition-group}
 
 	The <dfn>::view-transition-group()</dfn> [=pseudo-element=]
@@ -836,7 +840,7 @@ urlPrefix: https://wicg.github.io/navigation-api/; type: interface;
 	When a {{Document}}'s [=document/active view transition=]'s [=ViewTransition/phase=] is "`animating`",
 	the boxes generated by any element in that {{Document}} with [=captured in a view transition=]
 	and its [=element contents=],
-	except [=ViewTransition/transition root pseudo-element=]'s [=tree/inclusive descendants=],
+	except the [=tree/inclusive descendants=] of the ''::view-transition'' [=pseudo-element=] on that {{Document}}'s [=document element=],
 	are not painted (as if they had ''visibility: hidden'') and
 	do not respond to hit-testing (as if they had ''pointer-events: none'').
 
@@ -1102,10 +1106,6 @@ urlPrefix: https://wicg.github.io/navigation-api/; type: interface;
 			Note: This is [=marked as handled=] to prevent duplicate {{unhandledrejection}}s,
 			as this promise only ever rejects along with the [=update callback done promise=].
 
-		: <dfn>transition root pseudo-element</dfn>
-		:: a ''::view-transition''.
-			Initially a new ''::view-transition''.
-
 		: <dfn>initial snapshot containing block size</dfn>
 		:: a [=tuple=] of two numbers (width and height), or null.
 			Initially null.
@@ -1158,14 +1158,6 @@ urlPrefix: https://wicg.github.io/navigation-api/; type: interface;
 
 			Note: This is used to hold dynamic styles relating to transitions.
 
-		: <dfn>show view transition tree</dfn>
-		:: A boolean. Initially false.
-
-			When this is true, [=this=]'s [=active view transition=]'s [=ViewTransition/transition root pseudo-element=] renders as a child of [=this=]'s [=document element=],
-			with [=this=]'s [=document element=] being its [=originating element=].
-
-			Note: The position of the [=ViewTransition/transition root pseudo-element=] within the [=document element=] does not matter, as the [=ViewTransition/transition root pseudo-element=]'s [=containing block=] is the [=snapshot containing block=].
-
 		: <dfn>update callback queue</dfn>
 		:: A [=/list=], initially empty.
 	</dl>
@@ -1475,14 +1467,12 @@ urlPrefix: https://wicg.github.io/navigation-api/; type: interface;
 
 		1. Let |document| be [=this's=] [=relevant global object's=] [=associated document=].
 
-		1. Set |document|'s [=show view transition tree=] to true.
-
 		1. [=map/For each=] |transitionName| → |capturedElement| of |transition|'s [=ViewTransition/named elements=]:
 
 			1. Let |group| be a new ''::view-transition-group()'',
 				with its [=view transition name=] set to |transitionName|.
 
-			1. Append |group| to |transition|'s [=ViewTransition/transition root pseudo-element=].
+			1. Append |group| to the ''::view-transition'' [=pseudo-element=] on |document|'s [=document element=].
 
 			1. Let |imagePair| be a new ''::view-transition-image-pair()'',
 				with its [=view transition name=] set to |transitionName|.
@@ -1829,7 +1819,7 @@ urlPrefix: https://wicg.github.io/navigation-api/; type: interface;
 
 		1. Let |hasActiveAnimations| be a boolean, initially false.
 
-		1. [=list/For each=] |element| of |transition|'s [=ViewTransition/transition root pseudo-element=]'s [=tree/inclusive descendants=]:
+		1. [=list/For each=] |element| of the [=tree/inclusive descendants=] of the ''::view-transition'' [=pseudo-element=] on |document|'s [=document element=]:
 			1. For each |animation| whose [=timeline=] is a [=document timeline=] associated with |document|,
 				and contains at least one [=animation/associated effect=] whose [=effect target=] is |element|,
 				set |hasActiveAnimations| to true if any of the following conditions are true:
@@ -1978,7 +1968,7 @@ urlPrefix: https://wicg.github.io/navigation-api/; type: interface;
 					and |style| is in |document|'s [=document/dynamic view transition style sheet=],
 					then remove |style| from |document|'s [=document/dynamic view transition style sheet=].
 
-		1. Set |document|'s [=document/show view transition tree=] to false.
+		1. Remove all children of the ''::view-transition'' [=pseudo-element=] on |document|'s [=document element=].
 
 		1. Set |document|'s [=document/active view transition=] to null.
 	</div>