What happens when transceiver.stop() is called

Fix for Issue #878
Related to Issue #898

Rebase of PR #901

webrtc.html

@@ -6208,14 +6208,64 @@ <h2>Methods</h2>
             </dd>
             <dt><code>stop</code></dt>
             <dd>
-              <p>The <dfn><code>stop</code></dfn> method stops the
-              <a><code>RTCRtpTransceiver</code></a>. The sender of this
-              transceiver will no longer send, the receiver will no longer
-              receive. Calling <code>stop()</code> <a data-lt=
+              <p>The <dfn><code>stop</code></dfn> method irreversibly
+              stops the <a><code>RTCRtpTransceiver</code></a>. The
+              sender of this transceiver will no longer send, the
+              receiver will no longer receive. Calling
+              <code>stop()</code> <a data-lt=
               "update the negotiation-needed flag">updates the
               negotiation-needed flag</a> for the
               <code>RTCRtpTransceiver</code>'s associated
               <code><a>RTCPeerConnection</a></code>.</p>
+              <p>Stopping a transceiver will cause future calls
+              to <code>createOffer</code> to generate a zero port
+              in the <a>media description</a> for the corresponding
+              transceiver, as defined in <span data-jsep="stop">
+              [[!JSEP]]</span>.</p>
+              <p>When this method is invoked, the User Agent MUST run the
+              following steps:</p>
+              <ol>
+                <li>
+                  <p>Let <var>transceiver</var> be the 
+                  <code><a>RTCRtpTransceiver</a></code> object which is to
+                  be stopped.</p>
+                </li>
+                <li>
+                  <p>If <code><var>transceiver</var>.stopped</code> is
+                  <code>true</code>, abort these steps.</p> 
+                </li>
+                <li>
+                  <p>Let <var>connection</var> be the
+                  <code><a>RTCPeerConnection</a></code> object on which
+                  the <var>transceiver</var> is to be stopped.</p>
+                </li>
+                <li>
+                  <p>If <var>connection</var>'s [[<a>isClosed</a>]] slot is
+                  <code>true</code>, throw an <code>InvalidStateError</code>
+                  exception and abort these steps.</p>
+                </li>
++                <li>
+                  <p>Let <var>sender</var> be <code><var>transceiver</var>.sender</code>.</p>
+                </li>
+                <li>
+                  <p>Let <var>receiver</var> be <code><var>transceiver</var>.receiver</code>.</p>
+                </li>
+                <li> 
+                  <p>Stop sending media with <var>sender</var>.</p>
+                </li>
+                <li> 
+                  <p>Stop receiving media with <var>receiver</var>.</p>
+                </li>
+                <li> 
+                  <p>Set <code><var>receiver</var>.track.readyState</code> to <code>ended</code>.</p>
+                </li>
+                <li>
+                  <p>Set <code><var>transceiver</var>.stopped</code> to <code>true</code>.</p>                 
+                </li>
+                <li>
+                  <p>Mark <var>connection</var> as needing negotiation.</p>
+                </li>
+              </ol>              
               <div>
                 <em>No parameters.</em>
               </div>