Don't add too much listeners in BrowserWindowProxy

atom/browser/lib/guest-window-manager.coffee

@@ -44,7 +44,7 @@ createGuest = (embedder, url, frameName, options) ->
     guest.removeListener 'closed', closedByUser
     guest.destroy()
   closedByUser = ->
-    embedder.send 'ATOM_SHELL_GUEST_WINDOW_MANAGER_WINDOW_CLOSED', guestId
+    embedder.send "ATOM_SHELL_GUEST_WINDOW_MANAGER_WINDOW_CLOSED_#{guestId}"
     embedder.removeListener 'render-view-deleted', closedByEmbedder
   embedder.once 'render-view-deleted', closedByEmbedder
   guest.once 'closed', closedByUser

atom/renderer/lib/override.coffee

@@ -10,8 +10,7 @@ resolveURL = (url) ->
 class BrowserWindowProxy
   constructor: (@guestId) ->
     @closed = false
-    ipcRenderer.on 'ATOM_SHELL_GUEST_WINDOW_MANAGER_WINDOW_CLOSED', (event, guestId) =>
-      if guestId is @guestId
+    ipcRenderer.once "ATOM_SHELL_GUEST_WINDOW_MANAGER_WINDOW_CLOSED_#{@guestId}", =>
       @closed = true
 
   close: ->