Add Picture in Picture to unloading document cleanup steps

See #8906

Author: chrisn

source

@@ -113962,6 +113962,8 @@ new PaymentRequest(…); // Allowed to use
    object</span> is <var>window</var>, run the <span>context cleanup steps</span> given
    <var>transport</var>.</p></li>
 
+   <li><p>Run the <span>picture in picture unloading steps</span> given <var>document<var>.</p></li>
+
    <li>
     <p>If <var>document</var>'s <i data-x="concept-document-salvageable">salvageable</i>
     state is false:</p>
@@ -113986,10 +113988,10 @@ new PaymentRequest(&hellip;); // Allowed to use
    writing the following specifications are known to have <span>unloading document cleanup
    steps</span>, which will be run in an unspecified order: <cite>Fullscreen API</cite>, <cite>Web
    NFC</cite>, <cite>WebDriver BiDi</cite>, <cite>Compute Pressure</cite>, <cite>File API</cite>,
-   <cite>Media Capture and Streams</cite>, <cite>Picture-in-Picture</cite>, <cite>Screen
+   <cite>Media Capture and Streams</cite>, <cite>Screen
    Orientation</cite>, <cite>Service Workers</cite>, <cite>WebLocks API</cite>, <cite>WebAudio
    API</cite>, <cite>WebRTC</cite>. <ref>FULLSCREEN</ref> <ref>WEBNFC</ref> <ref>WEBDRIVERBIDI</ref>
-   <ref>COMPUTEPRESSURE</ref> <ref>FILEAPI</ref> <ref>MEDIASTREAM</ref> <ref>PICTUREINPICTURE</ref>
+   <ref>COMPUTEPRESSURE</ref> <ref>FILEAPI</ref> <ref>MEDIASTREAM</ref>
    <ref>SCREENORIENTATION</ref> <ref>SW</ref> <ref>WEBLOCKS</ref> <ref>WEBAUDIO</ref>
    <ref>WEBRTC</ref>