Prepare for removal of PeerConnectionObserver::OnError.

Prepare for removal of constraints to PeerConnection::AddStream.

OnError has never been implemented and has been removed from the spec.
Also, constraints to PeerConnection::AddStream has also been removed from the spec and have never been implemented.

R=pbos@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/23319004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@7605 4adac7df-926f-26a2-2b94-8c16560cd09d

talk/examples/objc/AppRTCDemo/APPRTCConnectionManager.m

@@ -170,7 +170,7 @@
 #endif
 
   [lms addAudioTrack:[self.peerConnectionFactory audioTrackWithID:@"ARDAMSa0"]];
-  [self.peerConnection addStream:lms constraints:constraints];
+  [self.peerConnection addStream:lms];
   [self.logger logMessage:@"onICEServers - added local stream."];
 }
 
@@ -243,16 +243,6 @@
 
 #pragma mark - RTCPeerConnectionDelegate
 
-- (void)peerConnectionOnError:(RTCPeerConnection*)peerConnection {
-  dispatch_async(dispatch_get_main_queue(), ^{
-    NSString* message = @"PeerConnection error";
-    NSLog(@"%@", message);
-    NSAssert(NO, @"PeerConnection failed.");
-    [self.delegate connectionManager:self
-                 didErrorWithMessage:message];
-  });
-}
-
 - (void)peerConnection:(RTCPeerConnection*)peerConnection
     signalingStateChanged:(RTCSignalingState)stateChanged {
   dispatch_async(dispatch_get_main_queue(), ^{