Don't leak listeners in embedder when guest is destroyed

atom/browser/api/atom_api_web_contents.cc

@@ -274,6 +274,9 @@ void WebContents::Destroy() {
     if (!destruction_callback_.is_null())
       destruction_callback_.Run();
 
+    // When force destroying the "destroyed" event is not emitted.
+    WebContentsDestroyed();
+
     Observe(nullptr);
     storage_.reset();
   }

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

@@ -40,9 +40,9 @@ createGuest = (embedder, params) ->
   destroyEvents = ['destroyed', 'crashed', 'did-navigate-to-different-page']
   destroy = ->
     destroyGuest id if guestInstances[id]?
-    embedder.removeListener event, destroy for event in destroyEvents
-  embedder.setMaxListeners 100  # we can have lots of <webview> in one page.
   embedder.once event, destroy for event in destroyEvents
+  guest.once 'destroyed', ->
+    embedder.removeListener event, destroy for event in destroyEvents
 
   # Init guest web view after attached.
   guest.once 'did-attach', ->

atom/renderer/lib/web-view/web-view.coffee

@@ -50,7 +50,6 @@ class WebViewImpl
     # heard back from createGuest yet. We will not reset the flag in this case so
     # that we don't end up allocating a second guest.
     if @guestInstanceId
-      # FIXME
       guestViewInternal.destroyGuest @guestInstanceId
       @guestInstanceId = undefined
       @beforeFirstNavigation = true