Added dataChannel.id text field to peerconnection.html

chrome/test/data/webrtc/manual/peerconnection_manual.js

Index: chrome/test/data/webrtc/manual/peerconnection_manual.js
diff --git a/chrome/test/data/webrtc/manual/peerconnection_manual.js b/chrome/test/data/webrtc/manual/peerconnection_manual.js
index 860469d9e987913e3a8148045d8c965934ef76a0..60e54db79becf43630aa1566769d372c094c6216 100644
--- a/chrome/test/data/webrtc/manual/peerconnection_manual.js
+++ b/chrome/test/data/webrtc/manual/peerconnection_manual.js
@@ -981,6 +981,12 @@ function onDataChannelReadyStateChange_() {
   var readyState = global.dataChannel.readyState;
   print_('DataChannel state:' + readyState);
   global.dataStatusCallback(readyState);
+  // Display dataChannel.id only when dataChannel is active/open.
+  if (global.dataChannel.readyState == 'open') {
+    $('data-channel-id').value = global.dataChannel.id;
+  } else if (global.dataChannel.readyState == 'closed') {
+    $('data-channel-id').value = '';
+  }
 }
 
 /**