unminimize windows with initial IconicState if first known on MapRequest

In that case, the MetaWindow is created, but it should also be unminimized
to satisfy the MapRequest triggered by the client, otherwise these would
stay minimized until they're shown explicitly by the user.

https://bugzilla.gnome.org/show_bug.cgi?id=774333

src/core/display.c

@@ -2296,22 +2296,34 @@ event_callback (XEvent   *event,
             {
               meta_compositor_add_window (display->compositor, window, xwindow);
             }
+
+          /* The window might have initial iconic state, but this is a
+           * MapRequest, fall through to ensure it is unminimized in
+           * that case.
+           */
         }
-      /* if frame was receiver it's some malicious send event or something */
-      else if (!frame_was_receiver && window)
+      else if (frame_was_receiver)
         {
-          meta_verbose ("MapRequest on %s mapped = %d minimized = %d\n",
-                        window->desc, window->mapped, window->minimized);
-          if (window->minimized)
+          meta_warning ("Map requests on the frame window are unexpected\n");
+          break;
+        }
+
+      /* Double check that creating the MetaWindow succeeded */
+      if (window == NULL)
+        break;
+
+      meta_verbose ("MapRequest on %s mapped = %d minimized = %d\n",
+                    window->desc, window->mapped, window->minimized);
+
+      if (window->minimized)
+        {
+          meta_window_unminimize (window);
+          if (window->workspace != window->screen->active_workspace)
             {
-              meta_window_unminimize (window);
-              if (window->workspace != window->screen->active_workspace)
-                {
-                  meta_verbose ("Changing workspace due to MapRequest mapped = %d minimized = %d\n",
-                                window->mapped, window->minimized);
-                  meta_window_change_workspace (window,
-                                                window->screen->active_workspace);
-                }
+              meta_verbose ("Changing workspace due to MapRequest mapped = %d minimized = %d\n",
+                            window->mapped, window->minimized);
+              meta_window_change_workspace (window,
+                                            window->screen->active_workspace);
             }
         }
       break;