Updated demos so they work on FF, the createOffer api cannot have null parameters according to spec. Same applies to createAnswer.

R=juberti@google.com

Review URL: https://webrtc-codereview.appspot.com/8219004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@5503 4adac7df-926f-26a2-2b94-8c16560cd09d

samples/js/demos/html/dtmf1.html

@@ -62,7 +62,11 @@ function gotStream(stream){
   pc1.addStream(localstream);
   trace("Adding Local Stream to peer connection");
   
-  pc1.createOffer(gotDescription1, null, null);
+  pc1.createOffer(gotDescription1, onCreateSessionDescriptionError);
+}
+
+function onCreateSessionDescriptionError(error) {
+  trace('Failed to create session description: ' + error.toString());
 }
   
 function call() {
@@ -94,7 +98,8 @@ function gotDescription1(desc){
   // Since the "remote" side has no media stream we need
   // to pass in the right constraints in order for it to
   // accept the incoming offer of audio.
-  pc2.createAnswer(gotDescription2, null, sdpConstraints);
+  pc2.createAnswer(gotDescription2, onCreateSessionDescriptionError,
+                   sdpConstraints);
 }
 
 function gotDescription2(desc){