[cssom][css-images][css-conditional] Re-up and apply the patch from #473

, switching CSS from interface to namespace. Closes #437.

css-conditional-3/Overview.bs

@@ -999,12 +999,12 @@ interface CSSDocumentRule : CSSConditionRule {
 <h3 id='the-css-interface'>
 The <code>CSS</code> interface, and the <code title=''>supports()</code> function</h3>
 
-The {{CSS}} interface holds useful CSS-related functions that do not belong elsewhere.
+The {{CSS}} namespace holds useful CSS-related functions that do not belong elsewhere.
 
 <pre class='idl'>
-partial interface CSS {
-  static boolean supports(CSSOMString property, CSSOMString value);
-  static boolean supports(CSSOMString conditionText);
+partial namespace CSS {
+  boolean supports(CSSOMString property, CSSOMString value);
+  boolean supports(CSSOMString conditionText);
 };
 </pre>
 

css-images-4/Overview.bs

@@ -685,11 +685,13 @@ Using Out-Of-Document Sources: the <code>ElementSources</code> interface</h4>
 	The <a idl>elementSources</a> Map object provides this.
 
 	<pre class='idl'>
-		partial interface CSS {
-			[SameObject] readonly attribute Map elementSources;
+		partial namespace CSS {
+			// [SameObject] readonly attribute Map elementSources;
 		};
 	</pre>
 
+	Issue(428): IDL namespaces don't support attributes yet.
+
 	Any entries in the <a idl>elementSources</a> map with a string key
 	and a value that is an object providing a <a>paint source</a>
 	are made available to the ''element()'' function.

cssom-1/Overview.bs

@@ -2812,16 +2812,23 @@ Utility APIs {#utility-apis}
 The <code>CSS.escape()</code> Method {#the-css.escape()-method}
 ------------------------------------------------------
 
-The <code>CSS</code> interface holds useful CSS-related functions that do not belong elsewhere.
+The <code>CSS</code> namespace holds useful CSS-related functions that do not belong elsewhere.
 
 <pre class=idl>
 [Exposed=Window]
-interface CSS {
-  static CSSOMString escape(CSSOMString ident);
+namespace CSS {
+  CSSOMString escape(CSSOMString ident);
 };
 </pre>
 
-The <dfn method for=CSS>escape(<var>ident</var>)</dfn> method must return the result of invoking <a>serialize an identifier</a> of
+Issue: This was previously specified as an IDL interface
+that only held static methods.
+Switching to an IDL namespace is *nearly* identical,
+so it's expected that there won't be any compat concerns.
+If any are discovered, please report
+so we can consider reverting this change.
+
+The <dfn method for=CSS>escape(<var>ident</var>)</dfn> operation must return the result of invoking <a>serialize an identifier</a> of
 <var>ident</var>.
 
 <div class=example>
@@ -2835,7 +2842,7 @@ The <dfn method for=CSS>escape(<var>ident</var>)</dfn> method must return the re
  <pre>var element = document.querySelector('a[href="#' + CSS.escape(fragment) + '"]');</pre>
 </div>
 
-Specifications that define static functions on the {{CSS}} interface and want to
+Specifications that define operations on the {{CSS}} namespace and want to
 store some state should store the state on the <a spec=html>current global
 object</a>'s <a spec=html>associated <code>Document</code></a>.
 <!-- https://github.com/w3c/csswg-drafts/issues/180 -->