Refactor the glib message-pump, and use it as the base for a gtk message pump and an X message pump.

views/widget/native_widget_gtk.cc

Index: views/widget/native_widget_gtk.cc
diff --git a/views/widget/native_widget_gtk.cc b/views/widget/native_widget_gtk.cc
index 6ecf284089d579c072612f96be3ae10ee9818b46..8d6e7fe2bfb4ac06253fbbbfe2e5e92af7f2bf30 100644
--- a/views/widget/native_widget_gtk.cc
+++ b/views/widget/native_widget_gtk.cc
@@ -1632,7 +1632,7 @@ void NativeWidgetGtk::OnMap(GtkWidget* widget) {
   // a workaround for a bug that X Expose event does not trigger
   // Gdk's expose signal. This happens when you try to open views menu
   // while a virtual keyboard gets kicked in or out. This seems to be
-  // a bug in message_pump_glib_x.cc as we do get X Expose event but
+  // a bug in message_pump_x.cc as we do get X Expose event but
   // it doesn't trigger gtk's expose signal. We're not going to fix this
   // as we're removing gtk and migrating to new compositor.
   gdk_window_process_all_updates();