[css-syntax] Add a 'top-level' flag to 'consume a list of rules', so stylesheets can ignore cdo/cdc but other uses will pay attention to them.

Author: tabatkins

css-syntax/Overview.html

@@ -3467,7 +3467,8 @@ <h4 id=parse-a-stylesheet><span class=secno>5.4.1. </span> <dfn
    <li> Create a new stylesheet.
 
    <li> <a href="#consume-a-list-of-rules0"><i>Consume a list of
-    rules</i></a> from the stream of tokens.
+    rules</i></a> from the stream of tokens, with the <var>top-level
+    flag</var> set.
 
    <li> Assign the returned value to the stylesheet's value.
 
@@ -3714,10 +3715,6 @@ <h4 id=consume-a-list-of-rules><span class=secno>5.5.1. </span> <dfn
    token</i></a>:
 
   <dl>
-   <dt>cdo token
-
-   <dt>cdc token
-
    <dt>whitespace token
 
    <dd> Do nothing.
@@ -3726,6 +3723,16 @@ <h4 id=consume-a-list-of-rules><span class=secno>5.5.1. </span> <dfn
 
    <dd> Return the list of rules.
 
+   <dt>cdo token
+
+   <dt>cdc token
+
+   <dd> If the <var>top-level flag</var> is set, do nothing.
+    <p> Otherwise, <a href="#reconsume-the-current-input-token"><i>reconsume
+     the current input token</i></a>. <a
+     href="#consume-a-qualified-rule0"><i>Consume a qualified rule</i></a>.
+     If anything is returned, append it to the list of rules.
+
    <dt>at-keyword token
 
    <dd> <a href="#reconsume-the-current-input-token"><i>Reconsume the current

css-syntax/Overview.src.html

@@ -2374,7 +2374,7 @@ <h4>
 			Create a new stylesheet.
 
 		<li>
-			<i>Consume a list of rules</i> from the stream of tokens.
+			<i>Consume a list of rules</i> from the stream of tokens, with the <var>top-level flag</var> set.
 
 		<li>
 			Assign the returned value to the stylesheet's value.
@@ -2682,8 +2682,6 @@ <h4>
 		Repeatedly consume the <i>next input token</i>:
 
 	<dl>
-		<dt>cdo token
-		<dt>cdc token
 		<dt>whitespace token
 		<dd>
 			Do nothing.
@@ -2692,6 +2690,19 @@ <h4>
 		<dd>
 			Return the list of rules.
 
+		<dt>cdo token
+		<dt>cdc token
+		<dd>
+			If the <var>top-level flag</var> is set,
+			do nothing.
+
+			<p>
+				Otherwise,
+				<i>reconsume the current input token</i>.
+				<i>Consume a qualified rule</i>.
+				If anything is returned,
+				append it to the list of rules.
+
 		<dt>at-keyword token
 		<dd>
 			<i>Reconsume the current input token</i>.