[css-syntax] Simplify the dimension state with the escape validity checker.

Author: tabatkins

css-syntax/Overview.html

@@ -2280,15 +2280,15 @@ <h4 id=dimension-state><span class=secno>4.4.12. </span> <dfn
 
    <dt>U+005C REVERSE SOLIDUS (\)
 
-   <dd> If the <a href="#next-input-character"><i>next input
-    character</i></a> is a <a href="#newline"><i>newline</i></a> or EOF, emit
-    the dimension token. Switch to the <a href="#data-state0"><i>data
-    state</i></a>. <a
-    href="#reconsume-the-current-input-character"><i>Reconsume the current
-    input character</i></a>.
-    <p> Otherwise, <a href="#consume-an-escaped-character0"><i>consume an
-     escaped character</i></a>. Append the returned character to the
-     dimension token's unit.
+   <dd> If the input stream <a
+    href="#check-if-two-characters-are-a-valid-esca0"><i>starts with a valid
+    escape</i></a>, <a href="#consume-an-escaped-character0"><i>consume an
+    escaped character</i></a>. Append the returned character to the dimension
+    token's unit.
+    <p> Otherwise, emit the dimension token. Switch to the <a
+     href="#data-state0"><i>data state</i></a>. <a
+     href="#reconsume-the-current-input-character"><i>Reconsume the current
+     input character</i></a>.
 
    <dt>anything else
 

css-syntax/Overview.src.html

@@ -1557,17 +1557,16 @@ <h4>
 
 		<dt>U+005C REVERSE SOLIDUS (\)
 		<dd>
-			If the <i>next input character</i> is
-			a <i>newline</i> or EOF,
-			emit the dimension token.
-			Switch to the <i>data state</i>.
-			<i>Reconsume the current input character</i>.
+			If the input stream <i>starts with a valid escape</i>,
+			<i>consume an escaped character</i>.
+			Append the returned character
+			to the dimension token's unit.
 
 			<p>
 				Otherwise,
-				<i>consume an escaped character</i>.
-				Append the returned character
-				to the dimension token's unit.
+				emit the dimension token.
+				Switch to the <i>data state</i>.
+				<i>Reconsume the current input character</i>.
 
 		<dt>anything else
 		<dd>