Cap chrome.mdns.onServiceList listeners per extension at 10

chrome/common/extensions/api/mdns.idl

Index: chrome/common/extensions/api/mdns.idl
diff --git a/chrome/common/extensions/api/mdns.idl b/chrome/common/extensions/api/mdns.idl
index 434d4b8187ff8912241fdae3b3d81a152dfbb31a..f199d2fb90d60fe2572504b7088734386cb37fdc 100644
--- a/chrome/common/extensions/api/mdns.idl
+++ b/chrome/common/extensions/api/mdns.idl
@@ -30,6 +30,6 @@ namespace mdns {
     // 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] static void onServiceList(MDnsService[] services);
+    [supportsFilters=true, maxListeners=10] static void onServiceList(MDnsService[] services);

[mark a. foltz, 2015/03/30 17:44:57]

Does this restrict the number of unique services listened for, or the total
number of event handlers registered with the API?

[Red Daly, 2015/03/30 20:28:33]

The total number of event handlers.

I'm unsure of the best approach if we want to directly restrict the number of
unique service types for which an extension can listen.  The restriction should
happen when onServiceList.addListener is called so an error can be returned.  I
think I could achieve that by modifying event.js
(https://code.google.com/p/chromium/codesearch#chromium/src/extensions/rendere...),
or somehow creating a "subclass" of EventImpl for onServiceList events, and
adding the restriction there.

Any thoughts?

   };
 };