[cssom] Use DOMString[] instead of DOMStringList

Author: Simon Pieters

cssom/Overview.html

@@ -1164,7 +1164,7 @@ <h4 id="extensions-to-the-document-interface"><span class="secno">6.2.3 </span>E
 <span class="idlAttribute">    attribute <span class="idlAttrType"><a>DOMString</a>?</span> <span class="idlAttrName"><a href="#widl-Document-selectedStyleSheetSet">selectedStyleSheetSet</a></span>;</span>
 <span class="idlAttribute">    readonly attribute <span class="idlAttrType"><a>DOMString</a>?</span> <span class="idlAttrName"><a href="#widl-Document-lastStyleSheetSet">lastStyleSheetSet</a></span>;</span>
 <span class="idlAttribute">    readonly attribute <span class="idlAttrType"><a>DOMString</a>?</span> <span class="idlAttrName"><a href="#widl-Document-preferredStyleSheetSet">preferredStyleSheetSet</a></span>;</span>
-<span class="idlAttribute">    readonly attribute <span class="idlAttrType"><a>DOMStringList</a></span> <span class="idlAttrName"><a href="#widl-Document-styleSheetSets">styleSheetSets</a></span>;</span>
+<span class="idlAttribute">    readonly attribute <span class="idlAttrType"><a>DOMString</a></span> <span class="idlAttrName"><a href="#widl-Document-styleSheetSets">styleSheetSets</a></span>;</span>
 <span class="idlMethod">    <span class="idlMethType"><a>void</a></span> <span class="idlMethName"><a href="#widl-Document-enableStyleSheetsForSet-void-DOMString-name">enableStyleSheetsForSet</a></span> (<span class="idlParam"><span class="idlParamType"><a>DOMString</a>?</span> <span class="idlParamName">name</span></span>);</span>
 };</span></pre>
 <dl class="attributes">
@@ -1185,7 +1185,7 @@ <h4 id="extensions-to-the-document-interface"><span class="secno">6.2.3 </span>E
 <dd>
 <p>The <code>preferredStyleSheetSet</code> attribute must  return the <a href="#preferred-style-sheet-set-name">preferred style sheet set name</a>.</p>    <p class="note">Unlike <code title="dom-Document-lastStyleSheetSet">lastStyleSheetSet</code>,    this attribute is initially the empty string.</dd>
 <dt class="attribute" id="widl-Document-styleSheetSets">
-<code>styleSheetSets</code> of type <span class="idlAttrType"><a>DOMStringList</a></span>, readonly</dt>
+<code>styleSheetSets</code> of type <span class="idlAttrType"><a>DOMString</a></span>, readonly</dt>
 <dd>
 <p>The <code>styleSheetSets</code> attribute must  return a list of the <a href="#style-sheet-set-name" title="style sheet set name">style    sheet set names</a> of the <a href="#style-sheet-set" title="style sheet set">style sheet sets</a>, in order    of the <a href="#document-style-sheets">document style sheets</a>.</dd>
 </dl>

cssom/idl/Document.idl

@@ -119,7 +119,7 @@ partial interface Document {
     sheet set names</span> of the <span title='style sheet set'>style sheet sets</span>, in order\
     of the <span>document style sheets</span>.</p>"
   ]
-  readonly attribute DOMStringList styleSheetSets;              // new
+  readonly attribute DOMString[] styleSheetSets;                // new
 
   [Documentation=
    "<p>The {@name} {@type} must, when invoked, run these steps:</p>\