ui: Don't use grab ops for grab negotation

Grab operations are now always taken on the backend connection, and
this breaks GTK+'s event handling.

Instead of taking a grab op, just do the handling ourselves. The
GTK+ connection will get an implicit grab, which means pointer /
keyboard events won't be sent to the rest of mutter, which is good.

src/ui/frames.h

@@ -82,6 +82,8 @@ struct _MetaUIFrame
   
   /* FIXME get rid of this, it can just be in the MetaFrames struct */
   MetaFrameControl prelit_control;
+  MetaButtonState button_state;
+  int grab_button;
 };
 
 struct _MetaFrames
@@ -95,6 +97,8 @@ struct _MetaFrames
 
   GtkStyleContext *normal_style;
   GHashTable *style_variants;
+
+  Window grab_xwindow;
 };
 
 struct _MetaFramesClass
@@ -153,8 +157,6 @@ void meta_frames_move_resize_frame (MetaFrames *frames,
 void meta_frames_queue_draw (MetaFrames *frames,
                              Window      xwindow);
 
-void meta_frames_notify_menu_hide (MetaFrames *frames);
-
 Window meta_frames_get_moving_frame (MetaFrames *frames);
 
 #endif