[css-position-4] No need for an explicit doc argument, element nodes always have an associated document. Fixes #8849

Author: tabatkins

css-position-4/Overview.bs

@@ -468,13 +468,8 @@ Top Layer Manipulation {#top-manip}
 
 <div algorithm>
 	An element |el| is <dfn export>in the top layer</dfn>
-	of an optional {{Document}} |doc|
-	if |el| is [=list/contained=] in |doc|'s [=Document/top layer=]
-	but <em>not</em> [=list/contained=] in |doc|'s [=pending top layer removals=].
-
-	If |doc| is not passed,
-	it's [=in the top layer=]
-	if it would be so for <em>any</em> {{Document}}.
+	if |el| is [=list/contained=] in its [=Node/node document's=] [=Document/top layer=]
+	but <em>not</em> [=list/contained=] in its [=Node/node document's=] [=pending top layer removals=].
 
 	Note: Specs should use this concept,
 	rather than [=rendered in the top layer=],
@@ -487,14 +482,9 @@ Top Layer Manipulation {#top-manip}
 
 <div algorithm>
 	An element |el| is <dfn export lt="render in the top layer">rendered in the top layer</dfn>
-	of an optional {{Document}} |doc|
-	if |el| is [=list/contained=] in |doc|'s [=Document/top layer=],
+	if |el| is [=list/contained=] in its [=Node/node document's=] [=Document/top layer=],
 	and |el| has ''overlay: auto''.
 
-	If |doc| is not passed,
-	it's [=rendered in the top layer=]
-	if it would be so for <em>any</em> {{Document}}.
-
 	Note: Specs should use this concept,
 	rather than [=in the top layer=],
 	when they are not manipulating the top layer itself,
@@ -507,45 +497,48 @@ Top Layer Manipulation {#top-manip}
 
 <div algorithm>
 	To <dfn export lt="add an element to the top layer | add to the top layer">add an element to the top layer</dfn>,
-	given a {{Document}} |doc|
-	and an {{Element}} |el|:
+	given an {{Element}} |el|:
+
+	1. Let |doc| be |el|'s [=Node/node document=].
 
-	1. If |el| is already [=list/contained=] in |doc|'s [=Document/top layer=]:
+	2. If |el| is already [=list/contained=] in |doc|'s [=Document/top layer=]:
 		* Assert: |el| is also in |doc|'s [=pending top layer removals=].
 			(Otherwise, this is a spec error.)
 		* [=set/Remove=] |el| from both |doc|'s [=Document/top layer=]
 			and [=pending top layer removals=].
 
-	2. [=set/Append=] |el| to |doc|'s [=Document/top layer=].
+	3. [=set/Append=] |el| to |doc|'s [=Document/top layer=].
 
-	3. At the UA !important [=cascade origin=],
+	4. At the UA !important [=cascade origin=],
 		add a rule targeting |el|
 		containing an ''overlay: auto'' declaration.
 </div>
 
 <div algorithm>
 	To <dfn export lt="request an element to be removed from the top layer | request removal from the top layer">request an element to be removed from the top layer</dfn>,
-	given a {{Document}} |doc|
-	and an {{Element}} |el|:
+	given an {{Element}} |el|:
 
-	1. If |el| is not [=list/contained=] |doc|'s [=Document/top layer=],
+	1. Let |doc| be |el|'s [=Node/node document=].
+
+	2. If |el| is not [=list/contained=] |doc|'s [=Document/top layer=],
 		or |el| <em>is</em> already [=list/contained=]
 		in |doc|'s [=pending top layer removals=],
 		return.
 
-	2. Remove the UA !important ''overlay: auto'' rule targeting |el|.
+	3. Remove the UA !important ''overlay: auto'' rule targeting |el|.
 
-	3. [=set/Append=] |el| to |doc|'s [=pending top layer removals=].
+	4. [=set/Append=] |el| to |doc|'s [=pending top layer removals=].
 </div>
 
 <div algorithm>
 	To <dfn export lt="remove an element from the top layer immediately | remove from the top layer immediately">remove an element from the top layer immediately</dfn>,
-	given a {{Document}} |doc|
-	and an {{Element}} |el|:
+	given an {{Element}} |el|:
+
+	1. Let |doc| be |el|'s [=Node/node document=].
 
-	1. [=set/Remove=] |el| from |doc|'s [=Document/top layer=] and [=pending top layer removals=].
+	2. [=set/Remove=] |el| from |doc|'s [=Document/top layer=] and [=pending top layer removals=].
 
-	2. Remove the UA !important ''overlay: auto'' rule targeting |el|,
+	3. Remove the UA !important ''overlay: auto'' rule targeting |el|,
 		if it exists.
 
 	Note: This algorithm is only intended to be used in special cases