Use closed event instead of destroyed event.

We now do not delete window manually so the destroyed would be delayed
until the object is GCed.

atom/browser/api/lib/browser-window.coffee

@@ -19,7 +19,7 @@ BrowserWindow::_init = ->
 
   # Remove the window from weak map immediately when it's destroyed, since we
   # could be iterating windows before GC happended.
-  @once 'destroyed', ->
+  @once 'closed', ->
     BrowserWindow.windows.remove id if BrowserWindow.windows.has id
 
   # Tell the rpc server that a render view has been deleted and we need to

spec/api-browser-window-spec.coffee

@@ -14,7 +14,7 @@ describe 'browser-window module', ->
       w.on 'loading-state-changed', (event, isLoading) ->
         if (!isLoading)
           w.close()
-      w.on 'destroyed', ->
+      w.on 'closed', ->
         test = path.join(fixtures, 'api', 'unload')
         content = fs.readFileSync(test)
         fs.unlinkSync(test)