mutter_plugin_begin_modal() and mutter_plugin_begin_modal() allow putting
a plugin into a "modal" state. This means:
- The plugin has the keyboard and mouse grabbed
- All keyboard and mouse events go exclusively to the plugin
mutter-plugin.[ch]: Add public API
compositor.c compositor-private.h: Implement the API
mutter-plugin-manager.c: When reloading plugins, make sure none of them
are modal at that moment, and if so force-unmodal them.
common.h: Add META_GRAB_OP_COMPOSITOR
display: When display->grab_op is META_GRAB_OP_COMPOSITOR forward relevant
events exclusively to the compositor.
http://bugzilla.gnome.org/show_bug.cgi?id=590754
67682a2683