Define getSVGDocument() in terms of content document

Additionally, make content document (also used by contentDocument) perform the same origin-domain comparison on the two documents involved.

Tests: web-platform-tests/wpt#20432.

Fixes #5094.

source

@@ -39550,19 +39550,13 @@ interface <dfn>HTMLAreaElement</dfn> : <span>HTMLElement</span> {
 
   <hr>
 
-
   <dl class="domintro">
-
    <dt><var>doc</var> = <var>iframe</var> . <code subdfn data-x="dom-media-getSVGDocument">getSVGDocument</code>()</dt>
    <dt><var>doc</var> = <var>embed</var> . <code data-x="dom-media-getSVGDocument">getSVGDocument</code>()</dt>
    <dt><var>doc</var> = <var>object</var> . <code data-x="dom-media-getSVGDocument">getSVGDocument</code>()</dt>
 
-   <dd>
-
-    <p>Returns the <code>Document</code> object, in the case of <code>iframe</code>, <code>embed</code>, or <code>object</code> elements being used to embed SVG images.</p>
-
-   </dd>
-
+   <dd><p>Returns the <code>Document</code> object, in the case of <code>iframe</code>,
+   <code>embed</code>, or <code>object</code> elements being used to embed SVG.</p></dd>
   </dl>
 
   <div w-nodev>
@@ -39571,28 +39565,21 @@ interface <dfn>HTMLAreaElement</dfn> : <span>HTMLElement</span> {
   the following steps:</p>
 
   <ol>
+   <li><p>Let <var>document</var> be this element's <span>content document</span>.</p></li>
 
-   <li><p>If the element's <span>nested browsing context</span> is null, then return null.</p></li>
-
-   <li><p>If the <span>origin</span> of the <span>active document</span> of the <span>nested
-   browsing context</span> is not <span>same origin-domain</span> with the element's <span>node
-   document</span>'s <span>origin</span>, then return null.</p></li>
-
-   <li><p>If the <span>nested browsing context</span>'s <span>active document</span> was created by
-   the <span data-x="navigate-xml">page load processing model for XML files</span> section because
-   the <span data-x="Content-Type sniffing">computed type of the resource</span> in the
-   <span>navigate</span> algorithm was <code>image/svg+xml</code>, then return that
-   <code>Document</code> object.</p></li>
-
-   <li><p>Otherwise, return null.</p></li>
+   <li><p>If <var>document</var> is non-null and was created by the <span data-x="navigate-xml">page
+   load processing model for XML files</span> section because the <span data-x="Content-Type
+   sniffing">computed type of the resource</span> in the <span>navigate</span> algorithm was
+   <code>image/svg+xml</code>, then return <var>document</var>.</p></li>
+   <!-- Ideally this would check a property of the document. -->
 
+   <li><p>Return null.</p></li>
   </ol>
 
   </div>
 
 
 
-
   <h4><dfn>Dimension attributes</dfn></h4>
 
   <p><span w-nodev><strong>Author requirements</strong>:</span> The <dfn><code
@@ -78766,9 +78753,9 @@ dictionary <dfn>DragEventInit</dfn> : <span>MouseEventInit</span> {
 
    <li><p>Let <var>document</var> be <var>context</var>'s <span>active document</span>.</p></li>
 
-   <li><p>If <var>document</var>'s <span>origin</span> and the <span
-   data-x="concept-settings-object-origin">origin</span> specified by the <span>current settings
-   object</span> are not <span>same origin-domain</span>, then return null.</p></li>
+   <li><p>If <var>document</var>'s <span>origin</span> and <var>container</var>'s <span>node
+   document</span>'s <span>origin</span> are not <span>same origin-domain</span>, then return
+   null.</p></li>
 
    <li><p>Return <var>document</var>.</p></li>
   </ol>