[cssom] Make LinkStyle.style nullable; editorial clean up.

Author: skynavga

cssom/Overview.html

@@ -1328,26 +1328,30 @@ <h4 id="the-linkstyle-interface"><span class="secno">6.3.1 </span>The <code>Link
   <p>The <dfn id="associated-style-sheet">associated style sheet</dfn> of a node is the <span>style sheet</span> in the list of  <a href="#document-style-sheets">document style sheets</a> of which the <a href="#style-sheet-owner-node">style sheet owner node</a> implements the <code>LinkStyle</code> interface.</p>
 <pre class="idl"><span class="idlInterface" id="widl-def-LinkStyle">[NoInterfaceObject]
 interface <span class="idlInterfaceID">LinkStyle</span> {
-<span class="idlAttribute">    readonly attribute <span class="idlAttrType"><a>StyleSheet</a></span> <span class="idlAttrName"><a href="#widl-LinkStyle-sheet">sheet</a></span>;</span>
+<span class="idlAttribute">    readonly attribute <span class="idlAttrType"><a>StyleSheet</a>?</span> <span class="idlAttrName"><a href="#widl-LinkStyle-sheet">sheet</a></span>;</span>
 };</span></pre>
 <dl class="attributes">
 <dt class="attribute" id="widl-LinkStyle-sheet">
-<code>sheet</code> of type <span class="idlAttrType"><a>StyleSheet</a></span>, readonly</dt>
+<code>sheet</code> of type <span class="idlAttrType"><a>StyleSheet</a>?</span>, readonly</dt>
 <dd>
-<p>The <code>sheet</code> attribute must return the <a href="#associated-style-sheet">associated style sheet</a> for the node, or <code>null</code>,    if there is no <a href="#associated-style-sheet">associated style sheet</a>.</dd>
+<p>The <code>sheet</code> attribute must return the <a href="#associated-style-sheet">associated style sheet</a> for the node or <code>null</code>    if there is no <a href="#associated-style-sheet">associated style sheet</a>.</dd>
 </dl>
 
 
   <div class="example">
-   <p>In the following HTML snippet the first HTML <code>style</code>
+   <p>In the following fragment, the first <code>style</code>
    element has a <code>sheet</code> attribute that returns a
    <code>StyleSheet</code> object representing the style sheet, but for
-   the second <code>style</code> attribute it returns <code>null</code>.
-   (Assuming the user agent supports CSS (<code>text/css</code>) and does
-   not support ExampleSheets (<code>text/example-sheets</code>).</p>
+   the second <code>style</code> element, the <code>style</code> attribute returns <code>null</code>,
+   assuming the user agent supports CSS (<code>text/css</code>), but does
+   not support the (hypothetical) ExampleSheets (<code>text/example-sheets</code>).</p>
 
-   <pre>&lt;style type=text/css&gt; body { background:lime } &lt;/style&gt;
-&lt;style type=text/example-sheets&gt; $(body).background := lime &lt;/style&gt;</pre>
+   <pre>&lt;style type="text/css"&gt;
+  body { background:lime }
+&lt;/style&gt;</pre>
+   <pre>&lt;style type="text/example-sheets"&gt;
+  $(body).background := lime
+&lt;/style&gt;</pre>
   </div>
 
   <p class="note">Whether or not the node refers to a style sheet is defined

cssom/cssom-source

@@ -1112,15 +1112,19 @@
   <!--{@idl(LinkStyle)}-->
 
   <div class="example">
-   <p>In the following HTML snippet the first HTML <code>style</code>
+   <p>In the following fragment, the first <code>style</code>
    element has a <code>sheet</code> attribute that returns a
    <code>StyleSheet</code> object representing the style sheet, but for
-   the second <code>style</code> attribute it returns <code>null</code>.
-   (Assuming the user agent supports CSS (<code>text/css</code>) and does
-   not support ExampleSheets (<code>text/example-sheets</code>).</p>
-
-   <pre>&lt;style type=text/css> body { background:lime } &lt;/style>
-&lt;style type=text/example-sheets> $(body).background := lime &lt;/style></pre>
+   the second <code>style</code> element, the <code>style</code> attribute returns <code>null</code>,
+   assuming the user agent supports CSS (<code>text/css</code>), but does
+   not support the (hypothetical) ExampleSheets (<code>text/example-sheets</code>).</p>
+
+   <pre>&lt;style type="text/css"&gt;
+  body { background:lime }
+&lt;/style&gt;</pre>
+   <pre>&lt;style type="text/example-sheets"&gt;
+  $(body).background := lime
+&lt;/style&gt;</pre>
   </div>
 
   <p class="note">Whether or not the node refers to a style sheet is defined

cssom/idl/LinkStyle.idl

@@ -6,10 +6,10 @@
 interface LinkStyle {
 
   [Documentation=
-   "<p>The {@name} {@type} must return the <span>associated style sheet</span> for the node, or <code>null</code>,\
+   "<p>The {@name} {@type} must return the <span>associated style sheet</span> for the node or <code>null</code>\
     if there is no <span>associated style sheet</span>.</p>"
   ]
-  readonly attribute StyleSheet sheet;
+  readonly attribute StyleSheet? sheet;
 
 };