Increase the maximum MDNS device limit from 64 to 2048.

chrome/common/extensions/api/mdns.idl

 // Copyright 2013 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.
 
 // Use the <code>chrome.mdns</code> API to discover services over mDNS.
 // This comprises a subset of the features of the NSD spec:
 // http://www.w3.org/TR/discovery-api/
 namespace mdns {
 
   // Represents a mDNS/DNS-SD service.
@@ skipping 19 matching lines @@
     // Immediately issues a multicast DNS query for all service types.
     // |callback| is invoked immediately. At a later time, queries will be
     // sent, and any service events will be fired.
     static void forceDiscovery(VoidCallback callback);
   };
 
   interface Properties {
     // The maximum number of service instances that will be included in
     // onServiceList events.  If more instances are available, they may be
     // truncated from the onServiceList event.
-    [value=64] static long MAX_SERVICE_INSTANCES_PER_EVENT();
+    [value=2048] static long MAX_SERVICE_INSTANCES_PER_EVENT();
   };
 
   interface Events {
     // Event fired to inform clients of the current complete set of known
     // available services. Clients should only need to store the list from the
     // most recent event. The service type that the extension is interested in
     // discovering should be specified as the event filter with the
     // 'serviceType' key. Not specifying an event filter will not start any
     // discovery listeners.
     [supportsFilters=true, maxListeners=10] static void onServiceList(
         MDnsService[] services);
   };
 };