Allow missing socketType in SocketInfo if socket is not connected

chrome/common/extensions/api/socket.idl

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 namespace socket {
   enum SocketType {
     tcp,
     udp
   };
 
@@ skipping 92 matching lines @@
   };
 
   callback RecvFromCallback = void (RecvFromInfo recvFromInfo);
 
   callback SendToCallback = void (WriteInfo writeInfo);
 
   callback SetKeepAliveCallback = void (boolean result);
 
   callback SetNoDelayCallback = void (boolean result);
 
-  callback GetInfoCallback = void (SocketInfo result);
+  callback GetInfoCallback = void (optional SocketInfo result);

[asargent_no_longer_on_chrome, 2013/05/29 21:31:07]

You can actually leave this as non-optional, since for callbacks we guarantee
the arguments will be sent to the callback as specified *unless* there is an
error. So for example in the chrome.tabs.get method I mentioned before, the
"Tab" argument to the callback is not optional but is omitted when an error
occurs. 

We could probably do a better job of documenting our error handling strategy,
because this is how most of our APIs work.

[Bei Zhang, 2013/05/29 22:14:51]

Done.

 
   callback GetNetworkCallback = void (NetworkInterface[] result);
 
   callback JoinGroupCallback = void (long result);
 
   callback LeaveGroupCallback = void (long result);
 
   callback SetMulticastTimeToLiveCallback = void (long result);
 
   callback SetMulticastLoopbackModeCallback = void (long result);
@@ skipping 199 matching lines @@
         SetMulticastLoopbackModeCallback callback);
 
     // Get the multicast group addresses the socket is currently joined to.
     // |socketId| : The socketId.
     // |callback| : Called with an array of strings of the result.
     static void getJoinedGroups(long socketId,
                                 GetJoinedGroupsCallback callback);
   };
 
 };