[css-images-3] Add 'none' keyword, mark angles as deprecated. Per WG resolution https://lists.w3.org/Archives/Public/www-style/2017May/0051.html #2726

Author: fantasai

css-images-3/Overview.bs

@@ -1422,12 +1422,12 @@ Image Processing {#image-processing}
 
 	<pre class='propdef'>
 	Name: image-orientation
-	Value: from-image | <<angle>> | [ <<angle>>? flip ]
-	Initial: 0deg
+	Value: none | from-image | <<angle>> | [ <<angle>>? flip ]
+	Initial: none
 	Applies to: all elements
 	Inherited: yes
 	Media: visual
-	Computed value: an <<angle>>, rounded and normalized (see text), plus optionally a ''flip'' keyword
+	Computed value: the specified keyword, or an <<angle>>, rounded and normalized (see text), plus optionally a ''flip'' keyword
 	Animatable: no
 	</pre>
 
@@ -1443,9 +1443,16 @@ Image Processing {#image-processing}
 	* The height (width) property applies to the vertical (horizontal) dimension of the image,
 		<em>after</em> rotation.
 
+	Values other than ''image-orientation/none'' and ''from-image'' are
+	<em>optional</em> to implement and <em>deprecated</em> in CSS.
 	Values have the following meanings:
 
 	<dl dfn-type=value dfn-for=image-orientation>
+		<dt><dfn>none</dfn>
+		<dd>
+			No additional rotation is applied:
+			the image is oriented as encoded.
+
 		<dt><dfn>from-image</dfn>
 		<dd>
 			If the image has an orientation specified in its metadata,
@@ -1818,7 +1825,9 @@ Changes Since the <a href="https://www.w3.org/TR/2012/CR-css3-images-20120417/">
 
 	- The <css>image()</css> notation has been deferred to Level 4.
 	- The <css>image-resolution</css> property has been deferred to Level 4
-	- The 'image-orientation' property has been marked as At-Risk.
+	- The 'image-orientation' property has been marked as At-Risk,
+		the ''from-image'' and ''image-orientation/none'' keywords,
+		and the <<angle>> values deprecated.
 	- Added the 'image-rendering' property
 	- Added the ''cross-fade()'' notation
 	- Defined <a href="#interpolation">Interpolation</a>