Cleanup ScreenshotManager and WindowManager

lib/WindowManager.vala

@@ -52,6 +52,14 @@ namespace Gala {
         IS_TILED
     }
 
+    [CCode (has_type_id = false)]
+    public class ActionKeys {
+        public const string INTERACTIVE_SCREENSHOT_ACTION = "interactive-screenshot-action";
+        public const string OVERLAY_ACTION = "overlay-action";
+        public const string PANEL_MAIN_MENU_ACTION = "panel-main-menu-action";
+        public const string TOGGLE_RECORDING_ACTION = "toggle-recording-action";
+    }
+
     /**
      * Function that should return true if the given shortcut should be blocked.
      */
@@ -176,5 +184,12 @@ namespace Gala {
          * @param direction The direction in which to switch
          */
         public abstract void switch_to_next_workspace (Meta.MotionDirection direction, uint32 timestamp);
+
+        /**
+         * Gets action command from gsettings and executes it.
+         *
+         * @param action_key The gsettings key of action. Available keys are stored in ActionKeys
+         */
+        public abstract void launch_action (string action_key);
     }
 }