Define the origin of non-initial about:blank documents

Fixes #255.

source

@@ -78218,6 +78218,19 @@ callback <dfn>FrameRequestCallback</dfn> = void (<span>DOMHighResTimeStamp</span
      </dd>
 
 
+     <dt>If a <code>Document</code> is the initial "<code>about:blank</code>" document</dt>
+
+     <dd>
+
+      <p>The <span>origin</span> and <span>effective script origin</span> of the
+      <code>Document</code> are <a href="#about-blank-origin">those it was assigned when its
+      browsing context was created</a>.</p>
+
+     </dd>
+
+
+     <dt>If a <code>Document</code> is a non-initial "<code>about:blank</code>" document</dt>
+
      <dt>If a <code>Document</code> was generated from a <span data-x="data
      protocol"><code>data:</code> URL</span> found in another <code>Document</code> or in a
      script</dt>
@@ -78236,17 +78249,6 @@ callback <dfn>FrameRequestCallback</dfn> = void (<span>DOMHighResTimeStamp</span
      </dd>
 
 
-     <dt>If a <code>Document</code> is the initial "<code>about:blank</code>" document</dt>
-
-     <dd>
-
-      <p>The <span>origin</span> and <span>effective script origin</span> of the
-      <code>Document</code> are <a href="#about-blank-origin">those it was assigned when its
-      browsing context was created</a>.</p>
-
-     </dd>
-
-
      <dt>If a <code>Document</code> was created as part of the processing for <span
      data-x="javascript protocol"><code>javascript:</code> URLs</span></dt>