[css-properties-values-api] Remove unregisterProperty. (w3c#764)

Author: andruud

css-properties-values-api/Overview.bs

@@ -74,7 +74,6 @@ dictionary PropertyDescriptor {
 
 partial interface CSS {
 	static void registerProperty(PropertyDescriptor descriptor);
-	static void unregisterProperty(DOMString name);
 };
 
 
@@ -100,7 +99,7 @@ following members:
 :   initialValue
 ::  The initial value of this custom property.
 
-The {{registerProperty()}} and {{unregisterProperty()}} functions {#the-registerproperty-function}
+The {{registerProperty()}} function {#the-registerproperty-function}
 --------------------------------------------------------------------------------------------------
 
 The registerProperty(PropertyDescriptor descriptor) method
@@ -230,38 +229,7 @@ the process via which specified values for that property are turned into compute
 is defined fully by the type selected,
 as described in [[#calculation-of-computed-values]].
 
-Properties can be unregistered using
-unregisterProperty(DOMString name).
-When it is called,
-it executes the unregister a custom property algorithm,
-with a name set to its sole argument.
-
-
-	To unregister a custom property with the name |name|:
-
-	1. Let |property set|
-		be the value of the
-		current global object's
-		associated Document's
-		{{[[registeredPropertySet]]}} slot.
-
-	2. Attempt to parse |name|
-		as a <>.
-		If this fails,
-		throw a {{SyntaxError}}
-		and exit this algorithm.
-
-		Otherwise,
-		let |parsed name| be the parsed value.
-
-	3. If |property set|
-		contains a record with a property name matching |parsed name|
-		(compared codepoint-wise),
-		remove the record from |property set|.
-
-		Otherwise,
-		throw a {{NotFoundError}}.
-
+	Note: A way to unregister properties may be added in the future.
 
 When the current global object's associated Document's {{[[registeredPropertySet]]}} changes,
 previously syntactically invalid property values can become valid and vice versa.