Make DataChannels Transferable and explain the implications

webrtc.html

@@ -4342,8 +4342,8 @@ <h3>RTCPeerConnection Interface Extensions</h3>
           </dd>
 
         <dt>RTCDataChannel createDataChannel([TreatNullAs=EmptyString]
-        DOMString label, optional RTCDataChannelInit dataChannelDict)</dt>
-
+        DOMString label, optional RTCDataChannelInit dataChannelDict)
+        </dt>
         <dd>
           <p>Creates a new <code><a>RTCDataChannel</a></code> object with the
           given label. The <code><a>RTCDataChannelInit</a></code> dictionary
@@ -5067,6 +5067,8 @@ <h3>RTCDataChannel</h3>
         </li>
       </ol>
 
+      <div class='idl' title='RTCDataChannel implements Transferable'></div>
+
       <dl class="idl" title="enum RTCDataChannelState">
         <dt>connecting</dt>
 
@@ -7750,6 +7752,19 @@ <h2>Security Considerations</h2>
     adversaries that can observe the network, so this has to be
     regarded as public information.</p>
 
+    <section>
+      <h2>Data Channels and Same-Origin Policy</h2>
+      <p>
+        Data Channels can be used to transfer data not only between
+        pages of the same origin but also between pages of different
+        origins. This potentially can be used to bypass existing browser
+        restrictions on mixed content (if one side is an HTTP origin
+        and the other side is an HTTPS origin). This sort of transfer
+        requires the cooperation of both sides, but can be done without
+        the cooperation of the server by using <code>postMessage</code>
+        to move a <code>DataChannel</code> from one origin to another.
+      </p>
+    </section>
   </section><!--section>
     <h2 id="sec-iana">IANA Registrations</h2>